There is no way on the Adobe site to disassociate a PayPal account. When you go to Your Account > Edit billing and payment > Edit payment method, you can change between payment methods on PayPal but not remove the account link altogether. While speaking with a customer service representative over live chat, I was told:
"I would like to inform you that we currently do not have the option to remove the saved details. However be rest assured as you have added the credit card it will not charge you on PayPal."
We went back and forth a number of times after that, but the agent was not able to resolve anything for me.
This seems like a major violation of GDPR Right to Erasure and I am highly concerned by this issue.