I'm keeping an eye on gamevault as well, but wanted to include to Retro gaming. I also like a web interface which gamevault is not currently planning on having. Right now I am experimenting with Romm. I can create a category for gog games and download each game as a zip archive. Not fully what I want but it works. I love that for a lot of emulators you can play roms directly in the browser.
I also saw mention of gaseous games and Gameyfin but haven't looked at them to closely yet.
I went with the supernote Manta and I love it. It is Android based, not Linux, and the ecosystem is really sparse. But you can easily side load F-Droid or the aurora store and that opens everything up. I have next cloud syncing my documents and moon reader giving me access to my calibre library.
It is first and foremost a note taker and drawing pad, sacrificing lights and color for writing feel. The writing feel is amazing though. No subscriptions, non replaceable pens, support for replaceable tip 3rd party pens.
It's cost is quite a bit more than remarkable 2 or the pinenote though.