Advice for a BF who is preparing to take in his GF from narcs.

I’m going to keep this pretty short and sweet. I 26M and preparing to take in my 24F gf who I’ve been dating for 3 years and plan to propose to. We’ve been doing long distance for that time. Her parents are very much run of the mill narcissistics from what I can tell. They swap from liking me to disliking me. Commenting on my job (for refrence I am a hydrogeologist and environmental consultant with a clear path to middle management) despite it netting over 100K salary in the long run once I’m in it for a while. For her they constantly maintain control and she’s an adult. Telling her where she ought to go and what to do. Again. 24F…. Plus a bunch of other really messed up stuff. I’ve already blocked her dad on linkd in. What advice can you give me to support her and make her departure more bearable? What should she do? Should she wait until the perfect time or give them no room to react and just book it? What has couples in a similar dynamic done to establish themselves and stop the overreach? I’m goingdetail light for privacy but I think you guys understand. Thank you!