Last time I tried the Media PC thing it ended up being somewhat of a nightmare. Had to spend significant amount of time setting up MadVR with my video player and get HDR HDMI passthrough working, but it was always very flaky. Occasionally an Nvidia driver update would break it completely. Dolby Vision wasn't even an option.

I really wanted to make it work, but it ended up being an annoying hassle. I got a Shield TV and it has been a much better solution.

Not sure if things have changed since then (~5 years ago).

The way I use mine is just running a standard desktop (with the scaling turned up so it's a bit more readable) and then browsing for the video files on my NAS in the file explorer. I have one of those Logitech wireless keyboard/trackpad combos for input. Obviously this is pretty clunky, but it's a hell of a lot less flaky than something like Kodi. I use Linux on mine, but you could do the same thing in Windows if you wanted.