Look at the D7500. Same guts as the D500 at 70% of the price. Only one slot but easy to manage the RAW + jpg and MOV files post shoot
I have had mine for 18 months and have not found any odd problems although I always apply the lens correction when importing the RAW image into Lightroom.
Try Geotag Pro app on your phone. Only $17 but it adds a step to your post processing.
Here is the backup scheme I have implemented for my photo and media collection (80,000+ photos). I have two 4Tb external drives that contain all media that are connected to my iMac. One is the main drive and the other is a duplicate that is incrementally backed up every night using a program called SuperDuper!! Lightroom Classic is set up to store the Lightroom Catalog on the external media drive. This gives a local backup of all of my photos. The media drive (which also contains the Lightroom catalog) is also continually backed up to a cloud service, Backblaze (about $50.year), for unlimited storage. The reason I chose this cloud service is they will provide a copy of your backup on a hard drive should you go through a house burn down scenario. Hopefully never have to use this feature but it would be much easier to deal with than waiting weeks for a restore via the internet.
The iMac's drive is backed up using Time Machine to another external drive which is also backed up to Backblaze.
Another nice feature of this is when I go away for the winter, I can take the two external drives with me and connect them to my MacBook Pro and have my entire photo collection with me.
The Sony 18-135 is my most used lens on my a6300.
I have been mounting 12" x 18" prints on 18" x 24" foam board (use spray adhesive) and then adding an 18" x 24" matt from Blick art supplies.
https://www.dickblick.com Very economical and no hassle with cutting matt board. This seems to be a standard size for poster frames and you can usually find something for around $25.
Your iMac comes with an app called Image Capture. Connect your iPhone to the computer with a USB cord and open the app. Unlock your phone and the image files will appear on the iMac in the Image Capture app. You can then specify where you want them copied to on your iMac.
This app is also useful if you want to bulk erase images from your iPhone.
Markets, Las Rambles, Gaudi. We were there during the unrest of the fall of 2017 and got to enjoy a demonstration of 400,000 people right outside of our apartment! A link to some photos....
https://flic.kr/s/aHsmaRKZXA
Have a look at any of the Sony 6000 series. The kit lens is compact and provides good coverage for landscapes and architecture. A telephoto zoom easily fits in a purse.
Just got home from a month's travel in Europe and here is my workflow for managing the photos I accumulated (about 9000 RAW). My home desktop is similar to yours, 27 inch iMac with mirrored external drives also backed up to the cloud (Backblaze). I have the smaller MacBook Pro Retina as a travel computer. A 500Gb SSD onboard. Not a lot of data stored on this machine and I clean out all unnecessary files & photos before I depart. Each day I download the photos on the SD card from the camera and my iPhone (used for geotagging) to Lightroom CC Classic which is running on the MacBook. If I have time, I can do some culling, processing etc. I carry enough SD cards so these are my travelling "backup".
When I return home, I export and merge the Lightroom library from the travel MacBook with the master library on my iMac Desktop. This way I preserve all of the edits that I did on the road. I can now finish off the culling and processing of the photos from the trip.
After my backup systems on the desktop have run and been verified, I can format the SD cards and trash the photos on the MacBook and am ready for my next trip.
I second the recommendation for the Three Legged Thing if you are going to be doing air travel. Check sizing and buy one that fits your checked bag. Mine also doubles as a monopod. Using it with a D7000 and 18-200.
I have had a a6300 for two years and it is now my travel camera rather than my Nikon 7200 kit. Bought the 18-135 lens this year to replace the two kit lenses and it is a nice lightweight DSLR alternative
Go with the 18-135. I have all three of those and the 18-135 is on the camera 95% of the time. Changing lenses is a pain and a source of sensor dust.