Trump did such a "bad job" in the first couple of months of the plandemic that Biden took credit for all the vaccines Trump produced. Trump was also given bad information by the WHO, who lied (under pressure from China) about it having a low chance of jumping species, and said that even if it did, it had low communicability chances.
Something else that didn't help was that the national emergency supply stockpile hadn't been restocked by any of the last few presidents who had made use of it, including Obama.
Did Trump handle everything perfectly? Nope. But he was the first president in a hundred years to have to deal with a pandemic. He did as well as anyone could expect, and certainly better than Biden would have, if Biden had faced nonstop roadblocks from the other side of the political aisle. If Trump had developed a literal cure for covid, AND cancer, democrats would have claimed it was in reality some secret eugenics cocktail designed to kill anyone who was a rich white male.
As for calling dead soldiers "losers", that's a claim with no verification, made by political enemies claiming he said something in a private conversation. That has about as much credibility as Amber Heard's testimony.
And Trump was no more immature than Hillary was after the 2016 election, the only difference was he didn't concede, because he knew his arguments actually had merit.
Finally, Trump may have pardoned people *implicated* in war crimes, but the left makes heroes of people who are guilty of immeasurable deaths and crimes against humanity, like Mao, Stalin, Castro and Che Guevara (to name a few) so you've got no room to complain.