ffmpeg

If that is a true priority, then you do not want Android TV.

Not even a raspberry pi with lineage os?

You would also be hesitant with youtube and netflix

I know. As I said, I’d be using Jellyfin for the most part.

in my case if I use mkv it starts transcoding and mp4 works fine on every device (desktop, android app, Chromecast, browser)

that surely is the issue. you can convert it to mp4 with ffmpeg: ffmpeg -i input.mkv -c copy output.mp4 If you want to keep subtitles this will probably work: ffmpeg -i input.mkv -map 0 -c copy -c:s mov_text output.mp4

you could double check the codec with mediainfo. also check it is mp4.

orgmode with neovim on PC and orgzly on phone. syncing with syncthing

Edit: I’m actually using orgzly revived, a community maintained version of orgzly, since orgzly is no longer mantained

For anyone who is interested in note taking in your everyday editor like vim or emacs, orgmode is an emacs tool (in neovim there is a clone plugin) for note taking, todos, agendas, etc. It uses a format similar to markdown, and a good part is that with the orgzly app you receive notifications for your events. So basically you can use orgmode as a calendar as well (I do!).

Neovim orgmode plugin github

for simplicity I think sxiv supports ebooks

I use Joplin. It supports syncing with OneDrive, Dropbox and NextCloud. Also supports encryption which is great if you are syncing to onedrive or dropbox.

I do it like this. Manage calibre on my PC, and copy the ‘Calibre Library’ contents to the server through ftp.