I almost went the direction you did, but I got frustrated enough with Tizen and garbage ads in Samsung's UI that I went the Android TV stick direction. It's an extra $40-50 per TV, but I feel a bit more in control; now I just don't allow any of the smart TV functionality to be enabled, and keep the devices disconnected from the network. Thanks to HDMI CEC, the integration with the Samsung remote is fine, though I typically use the Google TV remote instead.

Edit: also, last I checked, Tizen still has no Twitch app, which is a bigger problem since Twitch had Samsung remove the unofficial one. I don't really like Twitch much, but still. YouTube's Android app is also better than it's Tizen app, even on low-end Android TV sticks.

Jellyfin doesn't have an official native app, but there's a quasi-official version [1] you can run. That said, it does require putting the TV into dev mode so you can sideload the app.

I've been running it for a while now and it's actually pretty good, I haven't had any major issues except one freeze when searching, but I'm pretty sure that was the fault of the raspberry pi running jellyfin

[1] https://github.com/jellyfin/jellyfin-tizen