sorry, but I just don't believe a conviction will hurt Trump.
People are demurring now, but those soft supporters will find a way to justify still backing him, probably by claiming the trial wasn't fair.
I don't think the issue is the conviction itself as much as it's the inevitable spin the Republicans will coalesce with to mitigate it. They did that after Access Hollywood, January 6, etc.
That, and the conviction persisting in Americans' minds to election day are the bigger issues than them not caring at all. They just need to maintain caring, and thankfully, I think a conviction by a jury gives Biden the cover to talk more openly about Trump being an official criminal.