Question about iCloud storage

I have a 50GB plan that is almost used up. My wife has a Apple One plan 200GB that she shared with our family (including me), but my phone only syncs to my 50GB plan.

If I cancel my 50GB plan, data would still be available for 30 days. Would the data automatically transfer to a new plan, e.g. my wife’s Apple One plan? Or what happens when she cancels her Apple One plan and I start a new one? Would her data transfer over to the one I would buy and share?

Documentation on this is not clear, and I don’t want to lose my data.