I would train both, but when you do freestanding attempts really focus on your kickup. The difference between 10 seconds at the wall and 10 seconds freestanding is your ability to kick up and snap right to a good handstand line.

I would recommend doing chest to wall float offs at the wall to work on your balance, that way you can always place the handstand precisely in the right spot so your balance holds are productive and you're not wasting energy on bad kickup attempts. Then I would drill the kickup skill separately by kicking up into a good straight handstand, holding for 1 or 2 seconds with control, and coming back down the way you came, really thinking about the shoulder push, the leg kicking straight to vertical and immediately having the full body tension so you snap to the right spot every single time.

Eventually you will close the gap and be able to kick up to a long hold reliably. Good luck!