Applying Apple One iCloud storage to my subscriptions account

I use a different iCloud ID for storage and for Subscriptions. If as the article says, I apply the Apple One storage to my subscriptions ID, what happens to data in my existing iCloud storage. Will I lose that data?

Is there a way to transfer subscriptions and purchases from my subscriptions account to the iCloud account. I want to do this so I can stop using these two accounts but I have a lot of historical purchases on the subscriptions account. This is preventing me from upgrading to Apple One.