I'm looking into this as well. Banking in the United States has become a major problem for nomads, full time RVers, and cruising sailors because they have started using third party databases to flag PMBs and PO boxes and demand a physical address often substantiated by a
lease or mortgage. Multiple people with existing accounts have had their accounts frozen or closed because of this, and opening a new one has become impossible.
I'm not entirely sure how to get around this when your home is your
boat.