Yeah, transcoding entirely off - directly stream stored 720/1080p files (downloaded like that, although I did use handbrake on the pi once to transcode Space 1999 season 1. Took about 2 days I think).
Someone else was just talking about Wyse thin clients. I'm fairly sure that a $40 Wyse thin client out performs even the best Pi 4 (maybe 5 sometimes). If I can't find a way to fix mine, I may have to buy a few for uh...science. IIRC, they idle at about the same as the Pi