If/when this Big Beautiful Bill is signed into law, he will have the legal authority to do so. While federal courts can still hold the Trump admin in contempt for ignoring inunctions and orders, a provision in the bill will prevent federal courts from enforcing that contempt unless the complainant pays a bond. So basically, anyone wanting to sue the federal government has to pay a large fee. If not, then the government can ignorw the courts. The judge can tell Trump not to do something. Once Trump ignores the Judge, he can hold Trump in contempt. Once Trump continues to ignore the judge, that's it. No punishment or consequences whatsoever.
The perfect example of this is the Garcia case in which Trump admin deported the guy to the El Savador prison. Trump will be able to legally ignore the courts order to bring him back to America. While he is doing that now anyway, the Supreme Court has not held him in contempt yet. But once the law passes, if the Supreme Court finds the Administration in contempt there is nothing they can do to punish him.