I am in a similar situation than you, after spending quite a bit of time on this, I think there are 2 possible solution:

* The slightly hacky one: Find a virtual office in the U.S. whose address isn't flagged by Stripe + get a virtual U.S. phone number

* The proper solution: You need to transition to a UK Stripe account and provide your UK address/phone number. Even though your business is incorporated in the US what seem to matter is where you effectively do business. As long as you can provide a proof you are effectively doing business from the UK, Stripe will not have any issue with getting you a UK based Stripe account for US based corp.

This is all very weird, especially as you said, Stripe Atlas specifically encourages you go the registered agents route, only to then have the rug pulled from under your feet.