This nuisance suit is meant to counter the release of the NYC DA prosecutor resignation letter, and likely is in the hope of deterring other prosecution. Updates as they appear, although discovery with newly declassified material could prove probative in confirming other Trump hanky-panky.
My guess is this is Trump’s idea of a counter offensive that he can trade in exchange for asking others to back off their pursuit of him. “We drop this if you drop the X investigation and/or lawsuit”. Except it’s not going to work, and IS going to backfire.