When I went to BoA to apply for mortgage, they said i have no credit history (despite they lent me a car loan for a Mercedes just a few years ago which I paid off after a year, and that they know my wife has no job yet carry the only credit card of the family). BoA is so stupid. I am in fact in the process of moving my millions of assets out of BoA


Any other bank is going to do the same. They all look at the applicant's credit report.

Dave Ramsey touts that you don't need a good credit score. Or any credit cards. Every time he says that in a youtube video he gets roasted in the comments. In this day and age, it is necessary to have a good credit report or life can be quite difficult.

Anyway, it is not difficult to build up a good credit score. Put a $1000 or more (a bunch of money) in a savings account at a local bank. Then go in and ask for a 12 month personal $900 loan, pledging the account as collateral.
Make 3-4 monthly payments, then pay it all off. It only costs you a few bucks net.
Do this a couple more times, maybe at different banks.



My wife and I only use one credit card, and she is the primary holder, and I am just an added user

Not a good move.
Both husband & wife should have credit cards & bank accounts in their own name, listing the other as added user. Both should have their own good credit report & credit history. It does not cost you ANYTHING to have accounts in each name. There is no advantage in only one of you having primary account(s). And more than one credit card.

Think of all the things that can go wrong. Account gets hacked, card gets stolen, card gets blocked for possible fraud, death, etc.