I really doubt Congress is going to start forming factions. Republicans are all in it for the grift, except for a handful of looneys that really believe what they say (and, to their credit, are working on the Epstein files). Most Republican Congressmen do not care about their representees, definitely not enough to stick their own necks out. Two Republicans dissented on the "Big Beautiful Bill" purely based on spending concerns, which is the entire Tea Party Republican viewpoint. Two.
Your scenario also assumes that support of Congress is needed. The White House already has their Gestapo, ICE, as well as the actual US Military. They've broken Supreme Court orders, some of them unanimous 9-0 decisions.
I do believe the White House will continue to play along with Congress for as long as Congress obeys, them -- just to preserve the veil of normalcy. Should Congress actually attempt to impede the regime, they'll be ignored, or if deemed preferable, taken out.
We've seen the military attack citizens, seen ICE arrest members of Congress, and we've seen MAGA hold state legislators hostage. The same country that tormented innocent civilians in nations like Iraq, has turned its guns on its own. To assume that any legal action can stop the regime is to utterly ignore reality. There was nothing legal about George W. Bush's invasion of Iraq or Afghanistan. The US Military does not follow the law, it follows orders. The Constitution has been shredded in every sense but literal. The only way one can believe we have any protection is to presume that "it would never happen here"... in the face of "it" happening here.