Why isn’t Trump releasing Epstein stuff?

Because they never had any intention of releasing anything. It was something that grew on the internet and became popular with Trump supporters, so they promised to release more Epstein info (in particular a "client list") once in power. Now that they actually are being tasked with doing it, they realize they can't (because they don't have what they promised, because it implicates people in power, etc.) Trump is hoping it will go away now, but it doesn't seem to be going away.

In either case, Trump is in his second term and isn't going to resign over this, so he likely can just keep ignoring it until eventually it stops being talked about.