My HTPC is a NUC i7 11th gen. Plex works great out of the box and I had a hell of a time setting up vaapi in Jellyfin. I'll try Jellyfin again because I really would prefer to use it. Maybe third time's the charm.
Discussion
Are you using Windows, Linux, or Mac out of curiosity? I'm using Linux and it works quite well especially since it can fallback to the VAAPI integrated graphics driver built into the Linux kernel.
Fedora. IIRC Fedora stopped including support for Intel integrated graphics (it's been over a year since I last tinkered with it so I may be misremembering.) So I had to find the right collection of packages to get it working. I'm a little apprehensive about messing with it again since it works well.
Ah I can't speak for Fedora, not used it in ages, but I find that Debian related distros have excellent hardware support out of the box for the most part. I come across exceptions only very rarely. Alpine is good too.