I dont connect my tv’s os to the internet and use a dedicated mini pc for kodi or youtube/twitch in the browser. Cuz i have quite some performance in the mini pc; i also use to emulate some games.

AnduinOS?

Is it possible to sync between machines? Like with a centralized db selfhosted or with rsync?

Holy moly! Size of this app on fdroid is 414.4MB. Why is that?

Have you considered Bitwig Studio? It has native linux support.