Will secondary insurance cover a surgical procedure that isn’t covered by primary insurance?

Hi,

I’m transgender and am looking to get facial feminization surgery covered under gender affirming care and while my primary insurance through my employer does not cover this procedure, I live in a state where it is mandated that any state sponsored insurance covers this procedure for trans individuals. My thought process is to take out a secondary state insurance health plan come November to cover an upcoming surgery I have in the spring of 2025. However, I’ve been reading a bit more on secondary insurance and it looks like I would have to get a denied EOB first and then the secondary would take care of it? Is that true or can I just submit the prior authorization with the secondary insurance and not have to worry about the primary? I’m also worried about this “non primary clause” I saw here. Some other questions are:

-should I just drop my primary insurance through my employer and make the state insurance my primary? (It’s an expensive surgery so if it’s going to be a fight or a hassle with doing it through secondary I may just bite the bill and lay for out of pocket state insurance for all of 2025)
-who should I be talking to about this? My primary insurance or should I call the state insurance? (Not with them yet so call support is limited)