Thanks, I canceled earlier today and it said I can use everything until Nov 22. You are saying after its truly canceled Nov 22 ,I have 30 days to choose an iCloud+ storage plan?
According to article, you should have had option to select individual services like icloud 2TB.
According to other people from reddit, they were able to purchase icloud storage separately and get charged 10 bucks making the total storage for the last month to be 4TB.
If i were you, i would pursue 2 options:
1) Try to dig into settings more and find out how to purchase icloud separately. Sorry can't help here cause can't replicate the issue(no Apple one fan), but internet is scarce on this info. If successfully confirmed that you already have 2TB of icloud+ that kicks in after Nov 22 or after confirming you have 4TB because of added 2TB Icloud+ you could feel relieved.
2) If 1 didn't work, then i would actively prepay 10 bucks to friend/wife/fiancee to be added to family sharing of someone's 2TB icloud+. This gives you an option to figure yourself out and extra 1 month for 10 bucks when you hang on to smn else' 2TB.
3) I would not let it sit until Nov 22nd without actively doing 1 or 2, because
you might lose data with all these vague cancellation options. Apple made it intentionally unclear so people would just stick to Apple one cause of fear of change.