Oddly I think it is possible that UK Superheroes are a thing- the American comics did sell in the UK during WWII, and into the 60's onwards. Superman, Batman, Spider-Man etc all have brand recognition here, and
Marvel UK was a decently sized operation in the 80's and 90's.
Beano, Whizzer and Chips, Warlord etc all had Superhero type figures-
Eagle's Dan Dare from the 50's is an example (if more on a Biggles line), or Bananaman from 1980 or Marvelman from 1954 etc
ITTL, I could see companies like Marvel and DC producing localised Heroes and crossovers simply because the Commonwealth is too big a market to ignore. I am partly surprised a Captain Britain or Captain Commonwealth was not in the AltMCU. If they do not, then UK companies will certainly pick up the demand for escapist Superhero style tales.