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.
FWIW Google Workspace is indeed a subscription - it’s their business-focused offering, whereas Google One is consumer-focused. That said, there’s nothing preventing individuals or families from using Google Workspace - I do, and have for over a decade.
Workspace allows you to use your own domain and provide email/collaboration services for a number of people under the same domain.
For a personal Google One subscription, prepayment is definitely not available. You can be billed monthly or annually. Naturally, this is "pay in advance" so if you pay on October 1, your subscription lasts through October 31.
A few months ago, I canceled my subscription, and when I tried to re-enable autopay for it, I found that I could not, even though banner messages claimed I could. It turned out that I could not, in fact, re-subscribe until after the subscription had lapsed on its expiration day! I had no trouble doing that, and now, autopay is re-enabled for next year, but it sure was stress-inducing to just watch it expire.
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.