Left or right handed? This will determine where you mount it, and hence, how you mount it.
One good option might be the Aliengear ShapeShift set-up. It’s biggest draw, for me, is the use of the same holster with different mounts. This way, you never have to remove the pistol from the holster, exposing the trigger, greatly reducing the possibility of an accidental discharge. You could also buy separate mounting hardware for multiple vehicles, and multiple guns could use the same base.
While I’m mentioning Aliengear (I have absolutely no affiliation with them) they also sell molded shells. So you could just buy a shell and mount it where you want in the cabin. But there are two problems with this, IMHO:
1 - a molded shell only fits a specific firearm, so you don’t have flexibility in what you carry
2 - the gun has to be transferred from one holster to another, which I consider a safety issue
For me, personally, I’m a lefty, so even with a seatbelt on, I can still easily draw from the driver’s seat if need be. If I want to remove it from my body, I take the whole holster off and put it in either the door pocket, or center console. Luckily, in both of my vehicles, my holsters all sit snugly in the pockets and don’t slide around. Only issue is the center console makes for a right handed draw (again, lefty) but I regularly practice both sides at the range.