Setting up the controls in War Thunder can be very difficult because of the sheer number of options that there are. I have a Thrustmaster T16000m joystick and I have a mostly functional controls setup.
If you want to be able to look around with varying degrees of movement rather than by snapping to that 90° position, you need to enable relative control. Here's what my setup looks like:
Make sure you set Relative Control to Yes, and Correction to 0%. Control sensitivity, step, and multiplier will all change how fast the camera moves, so you can adjust that to your preference. You can set the exact same controls for the Y axis, just change which physical axis you're controlling it with.
Here's the rest of my setup for the view controls:
Most of these options can be adjusted based on how fast / smooth you want your camera to move. But I wanted to point out one part of the controls that shouldn't be overlooked. At the bottom of the list you can see the controls for Head Movement. These are usually only used when you have a head tracking device, but you can bind them to keys if you want, and I'll show you why.
Although you can now use the hatswitch to look behind you, many planes dont have a very good view, thanks to the armor plate behind your head, like in the Bf 109s:
I bound my head movement to the WASD keys so that I could get a little more view behind me.
Here's what you can see when you move your head up, and then to the side:
Much better huh? I've found this to be really helpful in battle. As for head tracking, many people will swear by it, but others who are excellent pilots will say you don't need it at all. If you're willing to put in the effort of making or buying one, then by all means go for it, but it's not at all a necessity.
Best Answer
There is not really a good answer for this as it's all preference but as for you problem with your A+X/ B+A you can just use your thumb to press both at the same time.
I usually press A not with the tip but a bit further down my thumb(I don't know the word in English).