The chase is a tried and true method, but there’s different factors of play. One WWE has never been a heel territory so they don’t do the chase as much as most other feds do. They’re more of a baby face on top that sets up and drops the heels, but even with that speaking, you typically don’t have a heel go over at mania to start the chase. You have the chase end at wrestlemania. So it would be better if Cena won at summerslam and then he had to chase and got it back at 42.
The bigger thing, though is the first time you have a generational matchup like this at wrestlemania sets the president. Whoever wins at wrestlemania is the guy that’s getting the seal approval from the company. You can’t get that back in the rematch. It’s just like when Charlotte erroneously went over Rhea Ripley and it took her years to get that seal back.