The money has been appropriated. DeSantis, as governor has the power to veto the appropriation. If he says he is vetoing it because he does not agree with funding sports facilities for sports teams then that would be one thing. But he has publicly said he is vetoing it because of what the Rays said about gun control and that is a clear violation of their First Amendment rights. DeSantis is using it as an election ploy knowing his veto will be found unconstitutional...some time after the election.
It is in no way a violation of their first amendment rights. They are not being prohibited from speaking. The veto will be upheld.