Nothing wrong with getting a realtor and a financing partner lined up to start the process. Do not put money on a house until you have orders in hand, at a minimum. You'll need orders to use a VA loan anyways.
A few years ago, my family was set to leave Base X with orders to Base Y. We had a realtor lined up and looked at several houses virtually (I was overseas and it was during the height of COVID madness).
The realtor was a godsend because she
A) gave us access to her MLS listings (what you see on Zillow/Redfin/etc is not going to have everything on the market)
B) would meet with us via Zoom regularly to talk about what we were looking for, the listings we liked, the various neighborhoods in our new location, and so on.
C) would walk through our favorite listings sometimes live on FaceTime and even show the commute to us to give us a sense of traffic in the area/major roads going to/from properties. She'd take lots of video and pictures for us, too.
D) was a bulldog for BS like shoddy renovations, smells, warped floors, etc.
We found her on a local-to-the-new-base military spouse website. She was a military spouse herself, so she was very understanding when I got extended a year and essentially backed out, even though she'd looked at a ton of houses and spent a lot of time on our house hunt. We ended up moving to the same area a year later but that wasn't a guarantee when we had to back out of all the house hunting upon my extension. We of course went right back to her and we found a great house through her services.
You don't pay a realtor til you close on a house and finding one that has experience working with the military will probably make any unforeseen changes easier to manage.
On the extreme end of your question, I would make sure once you get orders, if you decide to buy a house, you close after you have high confidence you won't get redirected somewhere. I'd also make sure your command and assignment team/detailer are made aware very clearly that you bought a house so they can factor that in if the idea of changing your orders crosses their desk. "The mission will come first" is always a thing but in today's military with retention issues being what they are, they shouldn't be as apt to screw people over with significant financial obligations. There's always that risk in our line of work, though.
