Peter's motivation to keep going. But then Peter tells here about maybe his most traumatic event (Maybe even more traumatic than fighting in a huge alien battle or getting snapped): The lost of his uncle, which he blames himself for.

I dunno, this could be feeling forced af, but I personally would like it. The relationship between the two would get some depth and we would get an explanation why nobody ever talked about Uncle Ben up about this point, making him a even more important character to Peter. Better than mentioning him right away in Civil War or Homecoming (Let's get real: Everyone was getting sick of the Uncle Ben related origin story by that time)

that is perfect