I switched to Jellyfin fully (from MythTV) shortly after its fork from Emby a couple of years ago.
I would suggest taking another look at it. It has really improved over the last couple of years and seems to have a very active development community that is engaged with its users. They have a dedicated subreddit and they post there a lot. [0]
I find the web interface functional enough, but the dedicated "Jellyfin" apps for Roku or Android are slightly disappointing still. They are definitely usable, just not as slick as better commercial apps. However, there is an excellent Jellyfin for Kodi addon, and that is what I use on PC and Android TV. [1]
I do have an actual mini ITX PC to host the media, an old-ish i3, which I would strongly recommend over something like a Pi.