NWH spiderman spoilers if you haven't seen it.
What if, don't hate me, instead of Gwen being Andrew Garfield Spidermans love interest, it was yn, and they were comforting Tom Holland Spiderman when Aunt May died, so when the other four came Andrew Garfield Spiderman seen yn and all the memories came back, but the yn with Tom, Peter 1, was one from a different universe (Tom Holland universe) instead of Peter 3's, so they have no idea who that Peter is.
I guess the same could work for Gwen too though. It just seemed easier with yn.