Mini PCs have more than enough resources to handle what you’re doing. Almost my entire home lab runs on 7th/8th gen mini PCs, which includes Plex and Jellyfin (working on migrating everything over to JF). Plex only ever threw a fit playing 4k stuff when my wifi started getting crowded with wifi cameras and zigbee devices. I fiddled with the channels, removed one of my 2.4 SSIDs entirely, and now everything is happy again.