I'm sorry but it's not great for beginners. It's a rolling bleeding edge distro that does not break often but when it does you need to know how stuff works to fix it.
6 years ago Proton was a thing. It worked out of the box with Steam games like it does today. Yes not everything was gold rated on protondb but it worked fine. I've been gaming on Linux since 2018.
ZFS encryption works fine but AFAIK it's complicated to do full disk encryption (for the OS drive) - this is easy to do with with luks.
ZFS is not complicated and just works - at least that was my experience. There is also a lot of help available online.
Yes, exactly. I push photos into the "import folder" of Photoprism. I don't manually trigger the re-index but I restart photoprism at night using a cronjob. I am not using settings like "PHOTOPRISM_AUTO_IMPORT". Contact me if you need me to investigate more.
I'm using syncthing-fork on Android for years on multiple devices without problems.