I tried that once with Nextdoor. They will group their mailings into different lists. The unsubscribe button only removes you from that list. To disable them all is 30+ clicks on the site once logged in. It's horrible.
I just went through this with Nextdoor in October. Well, I personally didn't do all 50 clicks, but I asked their customer service to do it and they confirmed I was unsubscribed.
Of course, I got a new message from them yesterday because they've added a dozen different lists since then and automatically opted everyone into them.
Is this technically permitted behavior under CANSPAM? Seems like a company could just create a new "newsletter / list" for every new marketing email they send.
It'd be up to a judge and/or jury to decide. If one can establish that the intent was to ignore one's attempts to unsubscribe, it'd be a pretty clear-cut violation. Most reputable senders have an "opt out of all further communications" checkbox (with some fine print about legally required and transactional emails). Pretty much the only way to bring a private action under CAN-SPAM though is to be an ISP and show "actual damages".