They CGI’d the costumes on the Avengers characters???
Yes they did. They also CGd some if their regular clothes on, too.
This jacket is CGd which I kind of get but also not really.
But yeah like while Evans is wearing the cap costume and most of the other sift costumes are real, the Black Panther costume is full CG, the hard suits they wore in Endgame were all CG:
Apparently there were practical issues with the suits because they didn't settle on a design until the last minute and didn't have the time to make them? (I could be wrong there)
the only real outfit in the MCU was probably becks mocap suit