Unfortunately, I don't see much hope overall unless someone other than Trump emerges as a conservative moral leader. Only from within can come change. And likely that would require the explicit formation of an alternative party. It is extremely frustrating to be vilified constantly through gross distortion and have attempts at bipartisan action be almost exclusively for show. Yet, trying to convince people of the misdeeds of Republicans does nothing but further isolate the parties.
As to standing up to Flynn, I think people should be calling in to AG Garland's office to advocate for pursuit of charges. Forget political fallout and optics. If the law supports an offense against the US, then prosecution should follow. The consequences of the behavior are already apparent.
I do not think Democrats should be playing along with the false appearance of will to govern in accordance with the structure of our political system. This does not mean they should do the same crap in return. It merely means they should not attempt to play along with the appearance of normal governance when it is demonstrated to be false. Where there are genuine attempts to govern appropriately in the interest of the people, regardless of how rare, hopeless, or insufficient they are, they should be respected entirely on their own without complaint by bringing in counter-example. If it becomes necessary to advocate for the public by using unilateral action, it should be done. But all attention should be toward public interest and exactly none toward politics/appearances.
Are we at risk of violent action to overthrow the Biden administration? I do not believe so. However, the foundation of America is currently crumbling under its own weight. A fantasy that Trump and Trumpism will go away because he is no longer President is not worthy of entertaining, mostly because the line of division had already been crossed (e.g. WaPo article about this during Obama administration highlighting Newt and others, and the host of media personalities [Rush, Tucker, Jones, etc.] who went full on echo chamber).