When you cancel your iCloud Storage 50GB subscription, it will end at the time of your next billing cycle. So you will still have 50 GB until that time.
See: Downgrade or cancel your iCloud storage plan - Apple Support If you downgrade or cancel your plan, the storage change takes effect after your current subscription billing period ends.* If you downgrade to the free iCloud Storage plan, you'll have 5GB of storage.
You must change the region to Norway by adding a Norway-based payment (bank/card/etc.) and address. Then after that, re-subscribe to iCloud Storage 50GB (or more) subscription again to retain using your 50GB storage.
I would advise to do a backup of your iPhone and data prior to this process just to be safe.
Sidenote: This might also be useful: Archive or make copies of the information you store in iCloud - Apple Support