We recently bought a cheap GMKtec NucBox G3 with an Intel N100 from Amazon, ($123 US). I used Sky42 Nexus (Libreelec 11) file for installation. So far everything, including 4k has played ok, but I did not and do not plan on testing every type of file. I whitelisted everything because our Sony XR75X90CL does really good upscaling, so I can not say how well it upscaled.
The only problem we have is with the Digital Clock Screensaver, I can not change the colors, it gives an error with the color picker helper script. The addon problem may be related to me copying the files from our Chromebook 3.
I have no idea how long this mini computer will hold up but so far I am really happy with the set up. I like it better than our Chromebox 3, Rpi4, Wetec Play 2 and others we no longer use. We use a shared database so I have no idea how well it will do with a large video collection etc.