Google Pay not being supported does indeed sound strange. I would have thought it would be on similar parity to Apple Pay, just maybe with spending limits?
Samsung Pay, if any are the ones I’d expect to be less well supported, though I was under the impression all would work anywhere there is a contactless terminal.
To add to @Peter_G’s suggestion, Samsung just launched their Samsung Pay Card in the U.K. which you may prefer to use over regular Curve. Choose wisely as you cannot currently have a Samsung Pay Card if you’re an existing Curve customer!