I would talk to different lenders. Many only have a 2yr look back for bankruptcy, so the fact it was in 2019 should still allow you to do a conventional loan through many other lenders.

Does your wife not have any other debt? Just a quick back of the envelope calculation, the PITIA on a $320K mortgage would be just a hair under the DTI requirements for most lenders (43%), which doesn't really give her much room for any additional debt in her name.

That said; there is nothing inherently wrong with the loan being in just her name if it's advantageous for PMI rates. She is taking on the financial risk, however. She would be wise not to put you on the title. If things don't work out between you and you're on the title but not the loan, you are entitled every bit as much to the house as she is without any of the financial obligation.