And the response from apple linked in that thread: https://9to5mac.com/2021/03/03/apple-card-apple-id-unrelated...

Allegedly unrelated to the apple card, your appleid just gets locked if you don't fulfill a trade-in.

Thanks! Macroexpanded:

Apple Card Disabled My iCloud, App Store, and Apple ID Accounts - https://news.ycombinator.com/item?id=26310817 - March 2021 (302 comments)