Is there a demo instance? I could use that for testing of it exists.

This. Save yourself some time and just go with Trillium. It does not have a native mobile app yet, but when it does, there'll be nothing to compare! :P

The issue could still be a fail-to-band issue if fail-to-band is looking at the user agent string (I'm not sure fail to ban looks at the user agent string, but it might be worth checking out.). The user agent string would likely be different on a mobile app versus a browser login.

Nextcloud maps works reasonably well although mobile view isn't great.

Trillium has attributes which are very similar and very versatile.

There is a mobile view plugin that makes the mobile pwa much more usable.

The two main ones that come to mind that I use are open sense and home assistant which both have add-ons to backup directly to next cloud

This repo may help: https://github.com/meichthys/foss_photo_libraries

Also not trying to be mean, but energy in the US is generally very cheap ($0.12/kwh where I am). With more regulation of the market, the reliability would probably increase but so would the price! (I see this happen first hand since I work in the industry)

Do you mean Memories?

Probably using Nextcloud Memories. Its very performant.

Nextcloud Memories is very fast. Photos is indeed a nightmare.