The Conservatives/Republicans are too passive and nonchalant in their approach.
Though they manage to stir the pot a bit during Committee hearings, they still are too over-confident with a sort of "right is might, and thus might is right" approach.
As you said, despite the energy displayed, there was no "red wave", but a tremor in the pond at best. And then there was the whole "Kary Lake" kerfuffle that might have discouraged quite a few.
Finally, there still is the issue of "weaknesses" within the party itself such as the Rinos, neocons and undecided fence-sitters; to the point that some of the Senators on the left (Manchkin, and Sinema to some extent) sometimes appear more reliable than some of the Reps who have been there since forever (Lindsey Graham for instance).
If Trump is arrested it will boost Trump's popularity among his base. It will probably not create new supporters though. But that popularity will be astroturfed by the Reps as used for the party's platform.
Trump has a HUGE bully-pulpit. That move will only bolster it to the point of him even winning the nomination anyway. It won't even be anywhere near close to 2016; but you can bet Reps delegates will hurry to flock around him, singing his praises and holding him as some sort of martyred idol, insert Marlon Brando's "look at what they did to my poor son" performance.
I "kind of" want, or would like, to see the whole Bragg's move being carried out though. From a legal point of view that would pretty interesting and quite the spectacle, not that the actual legal case holds any weight but in term of trials going on things are pretty quiet at the moment.
The whole call for protests is also interesting and reminiscent of Jan6. I didn't check, but I would assume it created some waves in the liberal world with Trump's message being understood as another call for insurrection.