Is there anyone who can advise me as a US citizen how I can open a personal bank account in the UK without being a resident there?
Unfortunately, it is a general knowledge that you won’t be able to open a personal bank account in the UK with a regular branch without being a resident.
However, you should be able to get an “off-shore” bank account with most UK banks as a non-resident, like I do. Although, these come with a mandatory minimal balance.
Otherwise, you would need to sign up with an online payment service provider such as Revolut or Wise.