Trump's ego was an asset in the private world, and it let him dominate in the GOP primary in 2016.
However, his ego was also why he had issues, because he kept causing/contributing to a lot of petty, stupid nitpicking arguments that were most about his pride, not anything of substance. It's also caused his campaign and political funds people to get rather...aggressive and callous in how they ask for/demand donations/participation in Trump's new social media stuff. They could not even be arse to cross check email vs phone vs text stuff during the election, to see if they were double/triple dipping on a person the same day, using nearly the exact same message, just in different forms.
Now, his ego and election year politics pushed him to rush vax's that have proven questionably effective at best, have been racking up adverse side-effects left and right, and Trump cannot admit he may have made a mistake rushing the vax's when therapeutics were available, and effective, as he himself noted several times in relation to HCQ and regeron, not to mention mono-clonal anti-body treatments.
Trump's ego and pride are his biggest failings, and he has likely doomed many of his base and America in general to a very fucked up future, because he could not/cannot man up and admit he made a mistake rushing the vax's. Those take years or decades to make and test for a reason.
There are reasons I want DeSantis on the GOP ticket in 2024, and not Trump, and the vax issue plus Trump's ego/pride are a big part of it. I haven't forgotten this is the same man who once tried to trademark the phrase 'You're fired.'