Another aspect to consider is how Peter's time travel might affect his personal relationships. If he goes back in time, he might be able to spend more time with his loved ones who were lost during the Snap. He could also use the time travel to figure out a way to bring them all back more effectively. And perhaps his actions in the past could make him a more experienced and confident hero in his own time, changing the way he approaches future challenges.
Well, one possibility is that Peter could use time travel to prevent certain events that led to his own death in Infinity War. He might go back and warn the Avengers earlier about Thanos' plan, which could change the whole course of the battle.
In the fanfiction world, Peter Parker's time travel in Endgame could also lead to some really interesting character interactions. Maybe he meets a younger version of himself or other heroes at a different time in their lives. For example, he could encounter a pre - super - powered Steve Rogers and have a conversation that changes Steve's perspective on something important. This could then have a ripple effect on the events of Endgame. He could also use his knowledge of future technology to help the past Avengers in some way, like improving their weapons or communication devices.