>> Perhaps you read the law differently but it does not have to be a public office. Once he declares or officially files for the Primary, he has to resign if the law is not changed by that time. <<
No, it PRECISELY says it must be a public office.
(2) No person may qualify as a candidate FOR MORE THAN ONE PUBLIC OFFICE, whether federal, state, district, county, or municipal, if the terms or any part thereof run concurrently with each other.
(3)(a) No officer may qualify as a candidate for another state, district, county, or municipal PUBLIC OFFICE if the terms or any part thereof run concurrently with each other without resigning from the office he or she presently holds.
There is no mention anywhere of a nomination.
WAIT A MINUTE!!!!
I just noticed that “federal” is missing from the list of offices in (3)(a)! Contrary to news reports at the time, there is NO reason he can’t run for president while serving as Governor. In fact, he could even BE governor and President at the same time, as unwise as that would be. He can’t run for CONGRESS and the presidency at the same time because those offices are concurrent and the elections are simultaneous. But this utterly doesn’t apply to DeSantis.