Why would minds change? We already know who the candidates are. None have surprises to produce.
Up until now, Trump has sucked all the oxygen out of the air with his theatrics and legal escapades. This will be the first opportunity some of the other candidates have an opportunity to make their case and get some exposure to otherwise open-minded voters.
Trump is a known quantity, to say the least. All General Election polls show him permanently stuck in the low to mid 40s when matched against Biden. He is currently in the process of turning off the open-minded group in the GOP, thus making it even less likely he could actually prevail in a General Election.
I agree there are numbers of the other candidates who have no business running, but there are a handful that should have an opportunity to be heard at this point. If someone should rise above DeSantis as Trump’s primary challenger, his instinct would be to unleash a vicious assault on that individual, although he may not have another $25M for that purpose, given his mounting legal bills.