Curious, while yes the car experience, as far as Android Auto goes, hasn't been ideal. Extending our Sandboxed Google Play compatibility layer to support Android Auto has been a top priority and it's nearly ready to ship and is imminent.

Maps don't 100% suck, while yes using alternatives to Google Maps is a YMMV experience, Google Maps itself works across the board. Location lock without sandboxed Play Services is focused on privacy preserving use of GPS/GNSS OS API and can take longer for first lock and is impactef as all GPS devices are to GPS issues. You can install sandboxed Play Services and disable this rerouting to enable network based bluetooth/wifi scanning for faster lock and indoor function. I use both Osmand and Google Maps with just GPS without issue.

As far as backups go, we plan to replace the current low quality Seedvault app with a new app developed by us, and it shouldn't be that far into the future. The app developed with us will be simpler, much more reliable, easier to use and will include much more app data. Seedvault fills that gap for now.

Regards Photos is this referencing cloud storage? I've found no issue using Cryptomator for cloud backups fine enabling yse of both mainstream hosts or self hosted solutions.

Appreciate things are never a one size fits all solution and am glad you've found something you're happy with. Responding for brevity and to be informative for others primarily but happy to hear more from you should you like to reach out.