He could veto, but the optics are beyond horrible and runs the risk of an override. Normally I'd say that won't happen, but given the number of Republican Congress critters who've signed the discharge, other Republicans now lining up in support, and notables like MTG going full rogue, anything is possible.
He could simply do nothing, and if both houses of Congress remain in session for 10 days after passage, the bill automatically becomes law without his signature. A rare event and an equally horrible outcome if he's heavily implicated in any documentation released. Given his antics, apparently he is or at least thinks he's heavily implicated.
If Mike Johnson ends the House session within those 10 days after passage, Trump doing nothing amounts to a pocket veto. Yet another horrible outcome for him.
This deal is splintering the whole magat movement. Donnie is damned if he does or doesn't by a trap of his own making. Trump trying to turn the Epstein mess into a political weapon against Dems, while being implicated himself, may very well turn out to be the biggest blunder in American political history. Had he disavowed and left the whole damn mess alone, he'd be in far better shape. Not off the hook, but with far more maneuvering room than he has now. But oh no. He just had to shoot his mouth off over and over again and embed it in what little minds magats actually have.