When Trump took office, the country was riding the wave of the economic recovery from the Great Recession. As long as nothing required action, he was OK. But when his first real challenge came along, he fell flat on his face. His total mismanagement of the Covid-19 pandemic brought a decade long economic expansion to a halt and cost 21 million Americans their jobs. His resistance to isolation methods early on, led to the same methods having to be implemented on a larger scale later. He kept promising it would "disappear" as it grew and grew. The unemployment rate reached 13.0% the largest quarterly unemployment rate in the history of the Labor Department's CPS (Current Population Survey).
He approved funds for use of recently developed Messenger RNA technology to fast track a vaccine but had no plan on how to get it distributed once it was approved. Biden had a plan to put in place on January 20, 2021.
How he would have reacted to a number of problems is scary to think about. We do know that he would have let Russia have its way with Ukraine. The bloodbath that would have caused boggles the mind. He was a "Do nothing," and it showed.