I'm not saying he's wrong. It could make him more sympathetic to some voters. But, a few things: We know this won't change the MAGA Cultists. They are ride or die with him. But...what about independents? I think there is a good chance they will see the reality - Trump was charged with a real crime, was tried and found guilty by a jury of his peers. They are the ones who aren't sucked into the right-wing media disinformation swamp. They will recognize that Trump has done illegal things to get into office....and he allegedly tried illegal shit to stay in power. And, while Trump wants to pretend this is a case of Biden forcing a prosecution, there is no evidence or any reasonable thought behind this. Just his usual axe to grind...Which right thinking people would recognize and understand.
Now, Trump himself loves to talk about polls. But the only important one is the one cast on election day. If polls were a lock, Clinton would likely still be president right now.