No, things would not change. Republicans would still control the Supreme Court. Over the last couple of years they learned that they can get away with anything: breaking any laws they want, straight out stealing money, building concentration camps, sending gestapo to murder people… They will not stop doing this only because Trump is dead.

Who exactly will take over after Trump is impossible to tell. Watch The Death of Stalin by Iannucci. This is exactly what will happen. A lot of infighting and backstabbing until new king of MAGA is crowned.