FWIW I use unsubscribe all the time and it’s quite effective, i don’t get the sort of garbage you describe. The only unwanted emails I get are after signing up for a new service and they start sending me marketing emails (which I almost certainly didn’t consent to so I’d say that’s spam, but at least I know where it’s from and these are the ones I unsubscribe from)
Edit: maybe it’s just that gmail spam filters work well?
Using "unsubscribe" on real businesses is perfectly fine, even if they added you to their mailing list using some sort of dark pattern. It almost always works and rarely has negative effects.
Using it on "enlarge your penis now" type spam isn't, to say nothing of outright phishing of course.
Edit: maybe it’s just that gmail spam filters work well?