I think he is talking about Dr Strange actor, I totally forgot he is a British actor.
there are plenty of brits in the MCU (because when your dialogue is for shit you really
need a good actor to sell it) but there aren't any british lead super heroes outside of whassherface as female captain america in What If and shes hardly "generic british white guy".
Benzedrine Cumpatch and Tom Holland are both playing Americans, Vision isn't 'British' in as much as he's effectively a voicepack, Odin, Loki, Wong, Mordo, The Ancient One, Klaw, Hobbit, et al are all side characters
e: oh and I guess Daredevil now, also not a british character