Transcoding anything >720p is painful.
I run ancient hardware for desktop/laptop >10yrs old apple stuff running linux. I consume media mainly via rpi4 or android.
What’s a minimum level system capable of trans-coding 4k video to x265 in at the very least real time? Is there a tiny trans-coding device out there somewhere?
Would a NUC do? How old or new to churn out 4k x265
Can I avoid hardware? Are cloud gpu’s a thing?
So I think you may not know about quick sync, an Intel transcoding acceleration feature of Intel gpus in Intel CPUs.
https://handbrake.fr/docs/en/latest/technical/video-qsv.html
There’s information about it for I think plex and handbrake and ffmpeg in general. This is how some people do real time transcoding for media servers. But I’m not an expert. I just hope you can be guided with easier search terms.