I don't think KYC laws keep people un-banked. According to the Federal Reserve only about 5% of adult Americans don't have a bank account. KYC is relatively easy to comply with, about the same as getting a library card. But if a person has a history of writing bad checks or running up overdrafts they can't get a bank account. And some percentage of Americans don't trust banks and remain un-banked by choice.

Source for your claim of 55 million unbanked American adults? That's 21% of the 2020 US adult population, and four times higher than what the Fed reports. If America had 55 million potential customers banks would be tripping over each other opening new accounts at McDonalds.