Those things are virtually silent, and can vesa mount.
If you want to turn your TV into Ultrabook class performer, buy it, they are considerably cheaper than anything else you can get to get VESA mounted hidden PC.
I use 5500u as my daily now for a month, only because 5700u's had month delay getting, so I got a cheaper option, and they returned me 100$.
I don't know how proshop had them a literal month before release, but I don't care.
I ride Ub 20.04 without any issues. I did not try a lot on it though, this box have VM's, browsers sometimes simple game like factorio.
One word of warning, if you need more ram on GPU, for now it's not configurable, stuck on 512MB. I could not find any way to change it. (I feel like might want 1GB/2GB when I have 32GB of ram)
In general Linux love AMD's especially GPU's.