A difficult circumstance.

My gut was to say cultivate as many relationships (low-key) as you can so that no matter where you landed, you would have at least some local contacts who would be able to introduce you into the local scene.

But as you say, if you become involved (high-key) and it might sway your career decisions, well after-the-fact, you go with the relationship because they're actually hard to come by imo... but because it hasn't happened yet, maybe it is best to wait so that you don't have the issue when it comes time to make that career decision.

We all have "requirements" of our partners... and one of yours could be "my partner must be willing to relocate when I relocate."

Don't know what else to tell you because I was never the proverbial military brat nor in that situation myself.