Trump didn't "praise" Cuomo. Trump said that the number of deaths in FL was the third worst, even worse than New York which was the fourth worst.
Calling New York the fourth worst in the number of deaths is hardly praising Cuomo, and the stat that Trump gave was not a "lie".
Do you know why you have to swear to tell “the truth, the whole truth, and nothing but the truth” when you testify in court? Because deliberately omitting relevant facts constitutes a lie, even if what you say is factual. So saying that Florida did worse than New York is a lie, because using the raw mortality numbers is not “the whole truth”. Using per capita numbers as well as the age adjusted numbers (accounting for the much higher population of senior citizens) is critical, especially since COVID was especially deadly to those over 65. Using age-adjusted figures, Florida is not even in the top 10 worst states. Adjusting for both age and per capita mortality, Florida is somewhere in the middle of the pack. And that does not even take into account the differences in the economic and educational impact.
But Trump praising Cuomo does tell us something about him. It says that Trump believes lockdowns, vaccine mandates, vaccine passports, sending COVID patients into nursing homes with vulnerable seniors were the right things to do. Because that is exactly what Cuomo did, and according to Trump, he did better than Desantis, who did none of those things except a short lockdown at Trump’s behest.