Easy fix.
Just don’t pass any law at all, and get the state out of doing marriages altogether. That’s fair to everyone.
I don’t think there’s an enforceable requirement for any state to issue marriage licenses to anyone.
So don’t do it at all.
Civil unions don't need licenses. You just sign a contract and poof, you are civilly unionized.
Get married in Church and do a Civil Union contract. The courts treat Civil Unions and marriages the same when there is a split.
Pastors won't have to worry about their tax status if they are merely performing religious rites rather than acting as the agent of the State in the performance of an official marriage.
Your tax status as a civil union is treated the same as a marriage. The only difference is that the parties to a Civil Union have more control.
Louisiana just considered ending recognition of marriage. They didn’t actually go there, but just considering it was a huge step.