SteveNSFW
Install prowlarr to troll your trackers and then radarr to deal with your movies. On Mac iirc its best to run them natively, and you can set up radarr to alert Plex that the new movie has arrived.
Recognize that there may be some costs involved: hard drives, a raspberry pi, VPN/VPS/seedbox, even just electricity.
Get a good VPN and use it for any torrenting you do from home. Nord is not a good VPN. (unless your government doesn’t care or you use a seed box, then do whatever)
Use public torrent trackers if you have to but: If you have some private torrent tracker accounts from yore, try to get them re-activated. Surprisingly they may have your old info. This will probably require IRC. If not, look into interviewing with RED, OPS, or MAM to learn the ropes, then use them to get invited into movie/TV/general PTs.
If you don’t like the sound of torrenting look into newsgroups. This will cost money in two ways: a newsgroup account and a news indexer.
Check out the arr suite, especially radarr and sonarr, to automatically get what you are interested in.