But will local voters be able to switch from MAGA republicans to non-MAGA republicans?

Probably not.

As was pointed out upthread, the biggest possibility of incumbents getting in a lot of hot water is if they try to mess around with Social Security. There's other things that could dramatically increase the chances of Democrats winning some of the general election fights - a recession or significant price increases triggered by a trade war, perhaps. But those aren't the sorts of things that are likely to lead incumbent Senators to lose a primary the way taking the wrong vote on Social Security might.

It's important to remember, I think, that most of what the Administration is doing is being well-received by Republican voters. Trump is doing exactly what much of his base wants him to do. IMHO, he's doing what some of the progressive base in the Democratic party has longed for their Presidents to do on certain issues they found important: take every single action he can regardless of whether it is likely to be found lawful or not. Don't negotiate against yourself, don't pre-emptively hold yourself back because your legal position is weak - do it, and let the other side stop you if they can. The ur-example of that on the Democratic side was student loan forgiveness during the Biden Administration, where Biden and other Democratic leaders were fairly certain that the President did not have unilateral authority to cancel student loans in the way he did, but they went ahead anyway, because their base wanted them to "fight" until they lost.

So the electorate in a GOP primary is going to love what Trump has been doing (for the most part), and would be more likely to turn out an incumbent who opposed those MAGA efforts rather than one who enabled Trump.