How well does jellyfin work on a rpi? How many simultaneous 1080p users with AVC\ACC media can it do? Active cooling?

rsync is indeed fiddly. Consider SFTP in your GUI of choice. I mount the folder I need in my file browser and grab the files I need. No terminal needed and I can put the folders as favorites in the side bar.

Slow and steady wins the race. Also helps to not be shit. looking at reddit.