Merge personal iCloud account and family iCloud account

Hi,

My wife and I have separate Apple and iCloud accounts. I upgraded my account to 2TB and made it a family iCloud account.

We both use iPhone 13s (iOS 18.1.1).

I have a Mac (Sequoia 15) and;

She uses a PC with windows 11 (current as of this afternoon)

She is able to sign into the FAMILY iCloud account.

We are using less than 1/2 of of our 2TB limit.

The problem we are having is that every few minutes an iCloud account log-in window pops up on her PC stating that iCloud storage is over the limit and her payment method needs to be updated. However when she tries to log-in, her password is not accepted. She did a FORGOT PASSWORD, changed the password and she is taken to the FAMILY iCloud account and then a few minutes later the iCloud account log-in window pops up again and refuses to accept the password that was just changed. We have been thru this cycle a few times now.

I assume that since she has an iPhone she still needs to have a personal APPLE account, is that correct?

Does she also need a personal iCloud account?