Make it so that players can directly enter desired seat by holding F1 to F12 outside the vehicle.
Yeah that's it.
I believe that at one point there were talks about making it so you had to get into vehicles from the correct doors/hatches. Perhaps that could be the way of going about this.
That will come with complete vehicle/inventory overhaul in 2077.
+1 to this, having the ability to not jump in on the open-top gunner seat of the light vehicles in the heat of battle would be a huge QoL improvement and save a lot of soldiers' lives!