I'm sure there is plenty of research being done into Newsome, but for it to come out now would be useless. He's already survived a recall, so until he runs for the WH, it's best to hold onto anything new until it can damage him. He's like DeSantis in that, in his state; he's bulletproof, so any shot taken would be wasted.
Now, if Biden wasn't running again, or if a year from now it's obvious that Biden can't even be "Weekend at Bernie's" into a second term, then I can see candidates on the right start throwing stuff out about him because then he becomes a worthy target.
There are in fact two things, science and opinion; the former begets knowledge, the later ignorance. Hippocrates