You might have hidden the toolbar (t) or changed the grid view to not show it. Double click an image and see if they are there on the bottom.

I think you either accidentally hid them, or an update reset something.

The catalog has the edit information and history. If you turn on sidecar files, they will have the latest edit information. I've moved LR raw images to other tools and most of the edits (if not all) come across.

I turn on auto saving the information to the sidecar files. This also kind of acts as a backup to your catalog file. Otherwise you need to select the image(s) and choose "save" to write the sidecar. JPEGs write into the files actual metadata with no sidecar. Not sure how DNGs work.

This have everything with you and a backup at home can be done a few ways.

The easiest option for "everything with you" is to have your primary "copy" all on one big external USB drive that you carry with you. Then, when you get home, back it up another "drive". A "copy" to another drive is not a backup; it is a copy including anything bad. A "backup" will have past versions so you can go back in time if you make a mistake. So, it does get complicated.

Personally, I don't really want everything with me. Images I take on the road and maybe some select recent ones is fine. So, I have my primary collection on a NAS with recent work on my local drive. The NAS does do actual versioned snapshots and it syncs to the cloud for an offsite backup. I've pulled from the cloud while traveling to get images too. A real backup follows 3-2-1. Three copies, 2 physical devices with one offsite. I have had drives fail. Backups are worth it. The NAS makes that easier and it is automated for me. If your backups don't "backup", they aren't backups.

I use Lightroom Classic and working off the NAS is not slower. I did some tests, and bulk exporting was faster somehow. That said, drive speed is not a limiter in Lightroom and I have a fast wired local network. Wifi to the NAS might be a little slower.

My home PC is fast and wired to the NAS. So, that is my primary Lightroom instance. Two main folders; "Import" and "NAS" with the folders underneath. When I'm home, card goes in reader, ingest to LR Import folder. Cull, edit and then move to NAS. LR catalog is on local SSD and preview cache is also there.
My travel laptop is a Mac. It has LR on it as well (you get two machines, just not supposed to use at the exact same time). When on the road, I do everything on the laptop like normal. When I get back, I export the laptops folder with the current images "as a catalog" from LR. I dump that to a temp folder on the NAS, then from my Main PC, I "import from another catalog" and get everything into my primary collection which also starts the automated backup process.

I'm going to stop here since there is a lot to think about in remote vs home, where you store and how you backup. A good NAS costs more than drives. It can do a lot including VPN to allow remote access.

Yes. For me, I close LR. Move the lrcat file then double click the file top open it with LR then it will open it in that location.

I like the setting to store the settings with catalog which creates a preferences folder you would also want to move.

The other files are cache that will be recreated.

Just use the Crop Tool. Set the ratio and apply to all images. I use it every time and it is there as of this most recent release.

I currently shoot with the D500, D750 and D5. While the D500 is very good for a crop camera in lower light, I don't bring it out when ISO is above 4,000 or 5,000. It does ok with noise, but the colors just aren't great. I'm shooting action so I need clean images with fast shutter at high ISO. To me, ISO 8,000-16,000 is high. Editors and clients don't care about the settings, they want clean, sharp images.

D500 is daytime filed sports or if the arena has nice lights (lots of older stadiums still aren't there yet).

D750 is great, but the AF is slow in the dark stuff which lowers my keeper rate. Mostly landscapes and events.

D5 looks as good or better at ISO 12,800 as the D500 does at ISO 5,000. Again, I look at colors and noise. I think my D5 images are cleaner then the D5 and I hit focus more often. A few editors I shoot for always like the D5 images better too.

I can't speak to the Z9, but other people I do shoot with have them and generally still like their D5's above ISO 6400. Some photogs are figuring them out and doing well. So, I think the Z9 is a learning curve with potential. Same group says they like their D6 and it is marginally better than the D5 in a few areas like color rendition, maybe noise and image quality.

I don't know your definition of low light or if you are shooting specific assignments with high ISO needs. This thread is too long to read, so I may have missed many details. I do think it is good to look at certain situations where you feel the D500 falls short. Then, I think we can help. Otherwise, you get a lot of posts about how proud people are of the decisions they made; which for them, they were good decisions.

Look at the files with Explorer. And, you may need to adjust a setting to see the file extension. That is the best way to know what type of file they are. Raw images to have embeded jpeg's that are used to show the preview and it can get confusing.

It will likely be around the $11,000 mark since that what the current F mount goes for. My 400/28 is at least 20 years old and is great. I'm hoping it will work on F mount.

Nikon USA is screwing over the third party repair shops (as of 2020 I think). Long story short, they can't get parts directly. They will try to get them, but no promise, so you may need to send it in to Nikon USA.

Kurtz in San Diego is great. Midwest Camera is also very good.

Kurtz is great (San Diego).

Midwest Camera is also good.

I've heard decent things about Robert's too.

Tamron is a good thing. Nikon USA no longer allows third party repair shops to get parts, so it is annoying.

70-200/2.8 followed closely by the 400/2.8. With COVID, I did a lot more sports and less portrait work.

Hill and Usher is great if you can't get it through your home policy.

Your post implies that you may make some money with photography. If your home insurance thinks you do (some will claim that having a web site makes you a pro) they may not cover you. If you are doing studio work or on location events, Hill and Usher is great. Their photo package has the stuff that most places will ask for when shooting on location.

If the Z9 has the same or better high ISO capabilities as the D5/D6, then I am very interested in the Z9. Next is that it will have to be as good or better in AF speed. Those are the two criteria that make me interested in the Z9. The Z9 is the first body in a while that has me interested. I don't like that the reported battery isn't very high (I get 3000+ with my D5).

Jury is still out, but I think the Z9 could be in my future before a D6. The D6 doesn't seem to provide enough over the D5, and the Z9 may not either, but I like what I see about the Z9.

It is a system that works well. If you just want one strap, then there may be a a more comfortable one out there.

I like the hand strap and have the shoulder one too. The shared "buttons" for connecting are nice. I like to take everything off if needed, and you can do that fast. Equally fast, you can move between things. I have the buttons on big lenses, bodies, pods etc.

I've shot low light events with the D750 many times. I run it manual with Auto ISO in matrix metering. I have auto ISO set to a max of 12,800. If you have any motion (people walking), I can bump up to 1/250+ and if it is a more still I can drop down to 1/60th and take a 3-burst (three quick shots usually gets one in focus and steady). F1.8 has a pretty low depth of field, so I might stay at 2.8.

I often shoot jpeg and use the in camera noise reduction as it is fantastic. RAW+JPEG gives you options. One thing to remember is that when you export a 24MP images to something for web or even an 8x10, most noise will be gone since you are reducing the number of pixels by nearly 50%+. Be confident and focus on the composition and story and don't worry about grain.