I don't unsubsubscribe unless I explicitly subscribed in the past. If I did not subscribe in the first place then it's spam (exception for small businesses who may not know better in which case I'll delete or unsubscribe).

I'll try unsubscribing once if it looks like a legitimate org, like someone I actually did business with but didn't expect them to email me. After that, it's going to the junk box to train the server what spam looks like.

There are unsubscribe headers that are used by mail user agents like mutt to unsubscribe from mailing list managers like mailman.

These are "scanner-proof" so far but support in clients like Outlook or Gmail is non-existent.