You what ? This same expert would value my wifes collection of 100,000 photos (many of which are prize winning shots) taken over 15 years on $30,000 worth of equipment probably the same at - well nowhere near $900.
The value of the photos has nothing to do with an expert. It is the value to you. And if even you cannot value them at all then why not just delete them after viewing them ? Certainly not worth backing up in anyway.
In fact the value of most photographers collections on your experts system of valuing is also worth - well nowhere near $900 so why are any of them bothering to backup ?

Although WD drives are pretty good you don't know if you have a drive failure until you try and read the drive (all of it not just a couple of specific files) by which time it is usually too late. At the very least (minimum once a year) you should copy each drive to another one to make sure that they can be read. If you get an error then is the time to panic. In my case since I have multiple copies I can just copy the unreadable files in from one of my other copies. However some soul searching as to whether those particular files are still required and you may decide not worth the trouble as long as the rest of the contents are okay. Now I have found over a 20 year period that if a drive develops a few read errors that reformatting and reusing the drive is NOT the way to go because 90% of the time the drive will fail again. It is not worth the risk. I have no idea what is the best way to deal with the potentially faulty drive (other than disposal) since why risk it.
You can also get a copy of a SMART reader and pass each drive through it maybe every 3 months. If errors show up here then make a copy of the drive before you do anything else. A SMART failure is a fatal error just sneaking up on you. Now for every person who tells you that they were able to read their backup drive 12 years after creation there will be 10 who had failures after that time. They won't tell you anything because it makes them look a little silly that they hadn't found out earlier. An unread backup hard drive is just waiting to get you. If you buy top end HDDs with a 5 year warranty and you get SMART errors invariably the supplier/manufacturer will accept it back for a replacement (or refund) with no problems. Note that 4 years into a 5 year warranty you will more likely get a refund and that is the way to go because a replacement will most likely be a refurb that only has the remains of the 5 year warranty. Assuming that your hard drives will last forever is a mistake.

Just to make this more relevant. One big second consequence of buying and only keeping one backup copy of files is what happens when the backup fails. Now the only reason why you were even going back to that backup is because the original was already history. And now your backup drive has errors and the backup copies are history. So all those contributors who keep 3 or more copies have demonstrated an ability to think past the law of first consequence. I keep 3 copies plus the original (one offsite) because I have seen too many people lose stuff. The very first happened 30 odd years ago when somebody came to me and asked if I could recover files from a floppy disk. I asked what was so important and it turns out that this guy had been paying somebody for 5 months to transfer data from a handwritten manuscript to electronic (a book he hoped to publish). The original failed and nobody had been making even the first backup. And it still happens today.

You are partly right re trying new things. However the older I get the ONE thing I try and do is learn from my, and others, mistakes. And one mistake I still haven't learnt yet is to think twice before buying stuff. This is a daily learning experience and I wish I would get it right all the time. I have a rule called "Rule of first consequences". This means that you have to think past the first consequence of doing something. It goes like this. Okay I'll just buy that because it solves this problem and that is the first consequence and is often an emotional response although not always. But what might the second consequence be ? So you think a bit longer and often find that the second consequence may not happen immediately but when it does it may be sufficiently bigger than the first consequence - so much so that the decision shouldn't have been made in the first place. This thinking pattern, in my case anyway, has only come with age. Buying camera gear is a prime example especially when I think of the number of lens I have bought then sold because I only ever used it twice. Deleting files eg surplus NEFs, first consequence is yea I have more disk space second consequence may not happen for several years but maybe you might want that NEF later but don't have it anymore. You might be surprised by the number of subsequent consequences to some of your actions. I have traced some things to a depth of 12-14 consequences and that 14th consequence results in death which must surely rule out going with the first consequence. However I can assure you that I don't run my life thinking things down to this level but getting older I am trying to think at least to 2nd and 3rd consequences. Money of course does mean you don't have to think too much because you can buy your way out of mistakes. And even this has consequences as even more of the worlds resources are used up. Hey I never wanted to get into this stuff so this is the last rant.

I can just see the conversations my kids would have when they clean out my photos.
"Hey whats all this stuff on dads computer"
"Oh I double-click on it and it won't open"
After several hours research (which won't happen anyway) this MIGHT be the next conversation.
"Hey apparently I can access these photos by buying this program and that program and playing around a bit"
"nah not worth the effort just delete them "
So even more of our history disappears.
I currently use Word 2013, it is now 2018.
I won't ever need any more features than I use now. Why pay $100/yr just to keep up ?
Sorry this is off track to the OPs issue.

Out of curiosity if you have a CC subscription that you let lapse for a couple of years, for whatever reason, and you then decide that you want to have a look at some of your raw files without re-enabling the subscription how do you do this ? These sorts of reasons might assist in making a decision about keeping or deleting the NEFs. I suspect that the dngs will be easily read later but not the nefs. Same applies to Office 365. Stop paying and lose access to all your spreadsheets and documents. Subscription models are a bit scary.

We have gone through from a D70, D200, D700, D800, D850 and never had an issue with battery doors coming loose. If you remove a battery for charging close the door immediately on a fresh battery. Never just leave them open for any reason. I suspect there might be a little "carelessness" going on here. One of my wifes friends has lost several lens by just "forgetting" about them when they have been changed and not put back in her bag. It is a "thing" that you have to see yourself doing and taking the extra time to make sure that you double-check those items. Believe me it gets worse as you get older.

Your problem will be a blocked head. It will probably be very hard to clean and if you eventually get it sorted (by cleaning rather than a new head) you will need to keep using it to keep it clear. I have had various Epson printers
and they give excellent prints BUT the heads often block. I have a high end Canon printer that doesn't block (even after a couple of years of none use) but the results aren't as good as the Epson so I keep it for doing things like printing out maps etc (A3). I have not replaced the last Epson because of this persistent head blocking and having to go through multiple head cleaning cycles. If the head was made for easy removal and cleaning then maybe I would look again.
Now I live in New Zealand where the cost of printers, ink and paper makes your eyes water. I found that local print houses are actually cheaper by the time you add up consumables costs. They print about 70-80cm wide and continuous length. Set up multiple photos to fit whatever size you want and send it off. Takes about 3 days. Costs about $35 (last one did anyway and that is NZ$), you have to cut them out yourself as they come on a roll but the quality is at least as good as any Epson. You can email the originals in and have the result delivered by courier in a cardboard tube for a few bucks extra so very convenient. I see no need for a new printer with all its cost and persistent hassles OTHER then the slight extra buzz you can gain by being able to print out NOW.

One of my previous clients was a TV production studio. Believe me the graphics design guys DID NOT use laptops. They used top spec components for everything and it was still too slow. The video editors use high end HP workstations. Some of my wifes Proshow Gold productions take 45 minutes to produce and I estimate they would take about 3.5-4 hours on either of our laptops. So I can only assume that the average laptop user doesn't attempt high end jobs or they have the patience of Jove. Being a non US citizen I have noticed that the queues at Disneyland with mostly US citizens are very patient so maybe it is a cultural thing. Me, I am interested in the starting minute and the finishing minute and the closer they are together the better.
When I was doing laptop repairs I couldn't believe how accepting the users were of pathetic performance (and these laptops weren't the cheapest models either). An upgrade to a SSD drive resulted in an acknowledgment of how bad they had been putting up with the previous performance.
However I guess whatever works for you is what you do even if sometimes I cannot understand it. It is what it is.

New here. I use both. A laptop for traveling with a 1TB SSD virtually used for backup only. Editing while away detracts from taking photos. At home I use a large desktop (actually a server tower case) with SSD for the OS and 12TB HDD of the revolving kind. There is absolutely no comparison between the performance of a laptop v desktop. My current motherboard/CPU (previously top models) has been in place for about 6 years. The case and PS is now well over 12 years old. The SSDs/HDDs are mounted in plugin SATA trays and upgraded as required. I plan on using the same case for another 10 years as upgrades are so easy with leaving all other devices in place. My monitors are a 32" Dell (4K) with Adobe RGB as standard and a 20" Dell with sRGB used in portrait mode.
I am retired now but previously sold and serviced computers for a living. I had a number of photographers as clients (including my wife who has a setup similar to mine) and a lot of them used laptops as their main PCs. Most of them constantly grumbled about performance and storage issues. Those with MACs even more so. There is a place for laptops depending on how you use them but the desktop will always win for speed and peripherals. A laptop and docking station is a partial solution but performance is still a letdown. Note that docking stations are harder to find now with some few of them now being USB-c attached and don't have the expandability of the older styles.