It's very wise to be thinking this way in preparation for your move.
If I were doing it again, I'd open free to maintain current accounts with several US banks before I left, as insurance. I was only a Wells Fargo banking customer and after several years of being able to easily bank from the UK, (2FA by email) they decided that they didn't want to support overseas customers any more, so closed all checking, savings and credit card accounts.
It was difficult coming up with an alternative from the UK. Many banks said they were happy to service overseas customers but would not open the account unless I was in the US at the time.