I’d argue she has avoided the public spotlight, thus she is not.
“Public Person” A description applied in Libel and Slander actions, as well as in those alleging invasion of privacy, to “anyone who has gained prominence in the community as a result of his or her name or exploits, whether willingly or unwillingly.”
Five actions that each, on its own, would make her a Public Person
1: Her modeling career
2: Her marriage to Donald Trump before he was in politics.
3: Her prominence as the leader in certain charities.
5: Her marriage to Donald Trump after his entry into politics.
5: Her speech at the RNC.
Open and shut matter. NY Times v. Sullivan was a bad decision, but is is settled law.