Any time I've had a similar subscription, you retain access for the full period.

The messaging has usually been something like: "Annual subscription cancelled at the end of current period. Access ends on 12/31/2026" (even if today is 6/1/2026)

That's why the "cancellation fee" comment is weird to me - there's no need to message that way, since "pay the rest of the committed period" seems to be a common (and at least to me, very understandable) way to handle this.

Even with monthly services, I don't think I've ever had an immediate loss of access - it's there until the end of the billing cycle. As it should be, IMO. The only exception would be if I force-deleted my account as well as that's a very explicit "I'm done-done" signal to the service provider.

Probably? There are services that are relatively nice and will let you use your membership until the last day (even for trials!), but there's also others that are non-refundable and will just yank your access.