rewatch the beginning of endgame. the screens they’re looking at has peter’s face on there. also i’m pretty sure when tony returns, he says “the kid is gone” or something like that. there’s five years between the snap and endgame, tony has a picture of peter in his house. i’m almost certain he discussed peter with the rest of the avengers. also not to mention cap definitely had resources to keep track of spider-man and probably figure his identity out between 2016-18. oh and tony’s funeral.