In my book, Trump can make as much of a fool of himself in public as he wants, as long as he gets the job done. Problem is, most of the time, he doesn't.
Reading behind-the-scenes accounts and reporting pertaining to this Administration, I don't see Trump as a genius hard at work behind the scenes, who only dons a dunce-cap when he speaks to his supporters in public. I see the same guy.
One time, I watched some direct footage of a Trump Administration cabinet meeting. The level of ass-kissing Trump's secretaries, and even VP Mike Pence, had to engage in order to hold the floor and the President's attention was embarrassing and downright dystopian.
It was how I imagine Chinese Communist Party conferences must be, in their universal fawning praise of President Xi Xinping.
There are bright spots in his Administration: Dr. Fauci and the other medical experts in charge of the Covid-19 response are mostly doing a good job. But Trump spends as much time publicly feuding with them and questioning their opinions, and spit-balling his own scientifically dubious "solutions," as actually listening to and following his experts' advice. I think his most competent officials have to waste as much time massaging their message to be palatable to the President as actually delivering good, reality-based advice.
As for an objective measure of Trump's performance, the proof is in the pudding of America's infection rates. We're now the global epicenter of the pandemic. It didn't have to be this way: other countries got their responses in order quickly, but we just didn't.
It's a complex problem, and there's blame to go around. But when it comes to a national/international issue, the buck stops with the President -- as Harry Truman once put it. The President can set the tone and marshal resources in a way that governors and other officials just can't. And there's already been plenty of reporting about the warning signs Trump missed in the early weeks.
Trump's extemporaneous remarks (and tweets) offer us a pretty direct peek behind the curtain into his thought-process and leadership style. And in the aggregate, over 3+ years, they paint a picture of a man not temperamentally fit to be President.
So we disagree, as expected, but you did answer my question ("I just haven't seen anything to warrant condemnation"), so you get points and an upvote for that.
And in answer to your questions: I'll post some comments of Trump's that I agree with in a bit. Rare, but it happens.