I don't know, is that Trump that has the polling problem or the GOP? And does even the GOP have it?
The GOP is almost certainly taking the Senate back in 2024. It seems more likely the Democrats will take the House back, continuing a Congressional split. Trump has an issue, but let's be flat out honest, so does the GOP. Trump pisses of Republicans, but the GOP pissed off women that didn't usually vote. Dobbs changed the dynamic, and while Trump can get people to vote for him that don't often vote, the GOP has almost nothing to offset the female who didn't typically vote vote. Without Trump, I think the GOP is in ever worse shape. The GOP loses a small chunk of those misogynistic racist fuck faces that vote almost exclusively Trump.
But the other side of the issue is the GOP have stuffed enough activist judges in the Federal Courts that they just go to one of them, and they get some outrageous ruling. And with SCOTUS a far-right juggernaut thanks in part of McConnell for maybe 20 years, there is a lot of jurisprudence that can be maintained even if the Democrats get the trifecta back.
Long story short, the GOP already won, even if they lose. Sad state of affairs, that. Which is why while General election matter, and we need to at least win there, the main battle is the state legislatures and attempted to wrest away the heavy handed state level gerrymandering which has solidified unnaturally conservative super majorities in purple states.