Nowhere near 17 this time.
After a four year delay, President Trump will be picking up right where he left off when 2020 election was stolen - running as a very popular incumbent.
A popular incumbent never faces much competition in the primaries - usually only one or two chronic losers who don’t mind humiliating themselves over and over.
In 2016 there was no incumbent in the race - that’s why we had so many contenders.
A bunch of them will continue to send up trial balloons, but as soon as Trump makes it official that he’s running, the polls will show he’s favored by over 90% of Republicans, and the rest will drop out before they ever raise a dime.
Even DeSantis, who is polling quite well, will declare that he’s not a candidate the minute Trump officially declares that he is running.
DeSantis is ripe for 2028, and he’s said if Trump runs, he won’t. The others are all just “shiny things”, meant to distract. I know you’re right, that they’ll drop out, hopefully.