According to the article, he did it because Good endorsed Ron DeSantis over him, or as Trump put it, “He came to me too late”.
http://ballotpedia.org/John_McGuire
Mr. McGuire just became a state senator as of Jan. 2024. He’s already trying to climb from state to federal, based on Mr. Good’s “disloyalty” to Trump for supporting DeSantis. McGuire supported keeping McCarthy, whereas Good supported getting rid of him.