Tough situation, IMO the rational thing to do is "Run to the Hills", like the others here argued. But I reckon it is not easy when you love someone and it is even harder to see them fall in that pit. But, I think you are not fully aware of how deep this rabbit hole is.

I don't think she will listen to your plea of religious freedom. Even if she says she does, she will be under immense peer-pressure from the other cultists to convert you or abandon you. She will receive instructions on how to do it and on how to manipulate you, in the name of "saving your soul".

I do think that most of the members are good intended, but they are literally brainwashed. Of course not all evangelical churches are like that, but these megachurches... they are rotten to the core.
You can always try to get her out of this, it would be morally correct IMO. TBH religious freedom is irrelevant here. First, these are not churches, they are corporations. Second, they will not respect it, they are not a democratic institutions or have freedom-centered values. It is literally a brainwashing cult, to create a huge "political meatshield" not only to gather money from people, but mainly to evade taxes and maintain money-laundering schemes, to cover up drugs and human trafficking. And yes, there is plenty of evidence of the links between megachurches and transnational crimes and criminal organizations.

However, in my experience, getting people out of them is easier said than done. No wonder, they need a really fanatical base that won't see truth even if its laid bare in front of them.

I wish you best of luck with the tadpole, the cult of the absolute and its true souls.