NUC is good for transcoding if you really need it. NUC11 i3 i think has 30w tdp and draws sub 10w at idle and does transcoding fine. Check specific HW codec support for your needs but stick to Intel because they will generally be the best in this space.
Also can confirm Jellyfin doesnt run well on a rpi4. No problem on a NUC.
Check the CPU, every NUC has a different one. An 11th gen i3 (i3-1115G4) will generally offer better performance than a N100 but a N100 may offer slightly better power efficiency since it was designed for it and is newer. Also when keeping in mind power draw and thermal efficiency, newer CPUs will usually do better. I personally would stear clear of older machines for that reason.