I would say that they're showing that Trump is dangerous. Biden is more than safe. He's decent, experienced, effective, and has a great track record.
The false right wing rhetoric against Biden seems to have some impact on democrats, and I'm not sure why. The alternative of Trump is so bad that even if all the false claims about Biden were true Trump is still vastly worse. I think a debate with high ratings would reveal how unbalanced Trump is in contrast to Biden. The only reason I see bits of Trump rallies is because I watch clips that are posted online. It's frightening. I doubt most of the voters have seen Trump in full mindless fury ranting about nonsense.
But alas. This is the new America, where nearly half (probably over a third) have no problem with Trump.
Which is a curiosity. I have to think many of these voters just are too absorbed in their everyday lives that news is not a priority.
I think Trump showed us that the protections in the Constitution don't work anymore. Checks and balances is gone now that you have congresspersons and Supreme Court justices enabling Trump and his crimes (your mention of Congress's failure to convict fits there). The idea that a sitting president is immune from legal proceedings has become a problem. The power of presidential pardons has been used against the country's best interests. Better safeguards are needed to protect national secrets from presidents.
The American system seems to require that a certain fraction of the electorate be aware of what American principles are and support them, and that the majority be decent and have the country's back. That's just not the case anymore. America seems to be at a tipping point in its transformation into something unrecognizable to Americans. Lying, bigotry, and thuggery have been normalized.
I never understood how much of an honor system our system of government really is, and how important it is to elect honorable and ethical people. It's taken a professional conman to really exploit the honor system's weakness of relying on ethical people, and this has invited many others willing to suspend dignity, duty, ethics, integrity, and even the law to gain power. I've said since Trump was gaining popularity in 2016 that America needs to hit bottom before it realizes that Trump kind of governing is anti-democratic, anti-American, and destined for a massive fight between MAGA and everyone else. I can't see moderate conservatives willing to see America collapse for the sake of a guy like Trump, and his greedy and selfish political allies. Germans in 1945 allowed their nation to be destroyed because their leader would not surrender when it was obvious that the war was lost. Will moderates really lose their way of life and assets because Trump and MAGAs want their vision of America at all costs?
This election will be the deciding factor.