It would not be at all sure that a Democratically-led Congress would begin the process of resolving "this mess." A Democratically-led Congress would likely make matters worse.You can be sure that a Democratically-led Congress would hold Trump accountable and begin the very long process of resolving this mess.
A Democratic majority in Congress would advocate opening the borders to illegal immigration as under Biden or would seek to make illegal immigrants citizens. A Democratic majority in Congress would waste taxpayers' money on leftist aims.