I basically give companies 0 strikes anymore, and assume the "unsubscribe" link is at best, a dark pattern that only unsubscribes me from that 1 out of their 100 "channels," and at worst, confirms my E-mail address. "Report Spam" immediately.

If I didn't intentionally request non-transactional mail, it is spam. By definition.

Mark it as such.

I assume the unsubscribe link is malicious - if I didn't ask to be subscribed, why would I trust an unsubscribe link? Spam baby spam.

I unsubscribe twice (allowing for one possible bug), then spam.

And, as others have noted, unsubscribe cannot involving going and logging into their system. If I need to do that, it generally goes directly to spam.

I unsubscribe, and immediately set up a filter to mark any email from their (sub)domain as spam. Too many sites keep spamming for a week or two after unsubscribing, that behavior deserves a reputation drop.

For whatever it's worth, I doubt that filtering to the spam label automatically has the same feedback effect in Gmail as a manual spam mark.

I'm well aware that some spam also use unsubscribe links as a signal to spam more. I use my gut to decide if I mark as spam and/or block or try the unsubscribe link if it exists.

My gut says unsolicited marketing emails, from popular sites I've never used before, like Brooks Brothers or Robinhood (especially after a "Welcome to ${site}!") or US public school event notification emails are all probably legit mistakes.

I could see even a public school system having issues with getting flagged as spam if they don't include an easy method to unsubscribe because then marking as spam+blocking becomes the best option in response to wrong address.

Another one I've been seeing more often is a missing unsub link and instead a "Manage Email Preferences" link.

Which of course you click and then have to go through a number of hoops to log in, confirm Email address, authenticate, etc.

At this point, I just mark those as spam as well.