Here is an idea for an effective way for Donald Trump to push back against the Republican establishment.
Trump should simply announce that any member of Congress who voted against the omnibus bill has his support for re-election, and he should invite those individuals to appear with him at campaign appearances or otherwise provide similar access for them.
Conversely, he should announce that any challenger to an incumbent member of Congress who voted for the omnibus bill has his support and access.
This could effectively have a chilling impact on the donor class that controls the Republican Party and seems hell-bent on destroying Trump. At the least it would raise the price tag for them to continue to control the members of Congress like puppets.