iPhone is set up with one Apple ID, but my Apple Card is under a different Apple ID. How to consolidate them?

OK, here's my dilemma. I've been using one apple ID for over 10 years. It has my contacts, notes, passwords (in Keychain), etc. Then about 2 years ago, when I was buying a new macBook, I signed up for an Apple Card. Unfortunately I gave them a different email. So as the result, my Apple Card is under a different Apple ID now, and I can't use it on my iPhone without losing my Keychain, contacts, notes, etc. (Moreover, the way that Apple Card is set up, I can't use it at all without an Apple device.) I was thinking that it's easy to consolidate two accounts into one, but it seems like it is not. (At least with Apple.) So thus my question, what is the easiest way for me to use my Apple Card on my iPhone?