I’ve been using OSMC on two of my TVs for years. First on RPis, then on Vero boxes. They connect via SMB to my NAS for content. OSMC/Kodi can play almost anything without needing wasteful transcoding. I use them daily.
For Netflix/Prime it’s either built in on the TV or running on a Firestick. Interestingly one can sideload Kodi on a Firestick, so an OSMC device isn’t necessary in that scenario.
It’s fixed. In general no distro is fail safe, recently even an immutable distro (our current hopeful advance in update reliability) had a hickup on an update that required manual intervention. It basically boils down to that it’s not possible to test for everything, we can only hope to continually add more test cases and improve human procedures based on post mortems.