Keep in mind that this is currently Kamala's peak in popularity, with the entire media machine and Democrat party running cover for her in highly coordinated fashion. It's only going to go downhill for her from here. They can't change the fact that she's a fundamentally terrible candidate, unlikeable, unintelligent and simply way out of her depth. There's a reason she got blown out of the water in the 2020 Dem primary before winning even a single delegate. She is simply a very unappealing candidate. Trump would be utterly foolish to not debate her. The Dems best strategy is to treat her just like they did Biden - keep her from talking in front of the camera as much as possible and just sell the idea of her, because the more people see of Kamala, the less they like her.
Trump doesn't want to debate her too soon while Dems can still change their minds. Trump wants them to be stuck with Kamala, and then force them to carry the albatross into election day. If Trump destroys her now they will just switch again.