I think those miniPC CPUs do a good job transcoding from what I’ve read, the N95 and N100. I already had older hardware set up when I added Jellyfin so I got a cheap nvidia Quadro P400 for the transcoding. If you’re setting up a new system though, I’d guess a Intel iGPU would be more than enough.
I’ve looked at https://www.elpamsoft.com/?p=Plex-Hardware-Transcoding before for transcoding comparisons.
What specifically isn’t working? I’ve got Jellyfin running on Docker with transcoding from a Nvidia GPU.
I pretty much followed the documentation here: https://jellyfin.org/docs/general/administration/hardware-acceleration/nvidia. I can share my docker-compose for that specific use case if you’d like.