I think it's a wash.
As noted in the trial thread, the crime in question here of hush money and covering up sex with porn stars is something that many low-information voters think politicians do all the time.
His base is already shored up, and Biden's is too.
I disagree about Biden's base being shored up. They seem much more hesitant.
I personally think this could get a bunch of reluctant Biden voters to finally back him, pr at least rile out considering Trump, especially in educated suburbs where I expect the verdict to have the biggest electoral impact.