I have a subscription to Google One (which is what you mean; Google Workspaces isn't a subscription, it's a suite of apps.)
It has some good perks. I am, however, petrified of going over the "free tier" storage limit, because if I do lose, or cancel, that One membership, then my Gmail will be completely disabled until I can bail out enough storage to go back under the 15GiB again. I think that's an extremely undesirable failure mode indeed.
That being said, searching for "unsubscribe" is definitely a genius shortcut, and I'm going to try it and see how it works for me. However, I also have enough personal correspondence over the years, with significant attachments that I'd need to scrutinize as well.