Trump has a problem following reports about Robinson’s comments identifying as a “black NAZI” and supporting slavery, as well as his Ashley Madison account.
You are not going to easily convert a hardcore Republican, but a lot of undecided voters do not follow politics closely. Having the Republican describing himself as a Nazi is about as clear as it can get, which will convice a lot of them to vote blue. It is also a good way of bringing people who would vote Democrat to actually vote.
He was already polling poorly and while it's basically tied in the polling, it's 47-47 and Trump won the state by a point in 2020 so the undecideds probably lean his way.
I tend to think a scandal of some other person can't hurt a presidential campaign that much, mostly just enthusiasm. So no, I don't think it will tank the Trump Campaign.
Gut says it moves from toss-up leaning Trump to true 50/50 toss-up.