Apple Card still tied to old Apple ID

Hello,

I've got an ongoing issue that I hope I can find help with here. When I originally setup my iPhone and registered for an Apple Card, my Apple ID was "username@domain.com" (keeping the actual account information anonymous for this post, of course). Sometime between then and now, about a year, I wanted to break ties with that email address and move everything into Apple's ecosystem, so I changed my Apple ID to "username@icloud.com". I made that new iCloud address the primary and eventually removed the original entirely. I've had no problems signing in with the now primary @icloud.com address, can register new devices, send/receive email, etc. From my iPhone, if I go to Settings > Wallet & Apple Pay, I see the "username@icloud.com" address under Transaction Defaults. It all seems like everything is in order.

However, the original Apple ID email address, "username@domain.com", is stuck associated with my Apple Card. Any notifications concerning the Apple Card (scheduled payments, statements, payments received) all go to the original @domain.com account email address. In fact, if I look at the new Apple Savings Account I just setup and go to Wallet > Savings Account > ... > Account Details > Account Information > I see, "username@domain.com" "This email address is associated with your Apple ID." and under it, my mailing address.

I think I've spoken to about 6 different layers of support from Apple and Goldman Sachs, everyone being eager to help, but I cannot seem to find anyone that's able to assist with getting this issue corrected. If there's anyone here that can point me in the right direction, I would be greatly appreciate it.