Is there a way of sending USD from a US account to Revolut, converting it to GBP in Revolut, and then sending the GBP to a UK account?
Yes, you simply send it to your USD account details. Keep in mind, that will be a SWIFT transfer and probably comes at a fee.
if the SWIFT fees from your US bank are too high you might consider using TW borderless as bridge.
after making a local USD transfer to TW Borderless you can either use TW’s debit card to top up your Revolut’s USD or make a SWIFT transfer for USD 3.30. once the USDs are with Revolut wait for a business day and exchange to GBP at a brexit blessed rate and then a local GBP faster payments to your UK account.
it’s tedious but very cost effective