Using SquareSpace With Email Other Than Google Workspace

I have had a SquareSpace website and was using it with an email address in a paid Google Workspace account. I cancelled the Workspace account and am trying to use my email address with my SquareSpace, but I can't figure out how to make it work. The domain is registered on NameCheap. I tried NameCheap's private email, but it will not work unless I point the domain away from the SquareSpace servers to NameCheap.

All I want is my website with a working email address. Any tips?