Letting Casty play through it is perfectly defensible. Playing him less would also be defensible. But who would you replace him with that's actually better?
If July comes and he's never gotten on an actual hot streak, then you go find someone better, difficult as the big picture will still be in terms of the guy's ego and contract. But they can't let him go wire to wire like they did in 2022 (that said, that team almost won the World Series).