We'll have to wait for Catalist to release their analysis of the 2024 electorate, but while it isn't the sexy answer, backlash against inflation seems to be the biggest driver based on what evidence exists today.
Partisan Rs are currently making the same mistake that all winning sides do in these contests in assuming that their win means that American voters love every single position they take on every single issue. And that's just not the case.
(Full disclosure, I made this mistake too in 2020 at times too, so I am as guilty as anyone)