Take a look here:
In order to change the input keys to toggle your custom cameras, you will need to go into your Controls Settings. Under your Keyboard profile search in the Assigned search bar for “Custom”.
Under the Cockpit Camera tab, you will see multiple “Load Custom Camera” settings. Change them all from ctrl+alt+1 or ctrl+alt+2 to 1, 2, 3, 4.
Now you can go into your plane and set up custom views by placing your camera using your set controls and pressing ctrl+alt+1 to save that position to Custom View 1, ctrl+alt+2 for Custom View 2, and so on. (If you don’t know which keys to use to move you views around, they can be found under the Cockpit Camera tab and translate up/down/left/right, look up/down/left/right)
Then check to see that 1, 2, and 3 pull up your preset views. That’s all. You can change them on the go, its that easy.
I personally use alt+1, alt+2 for Custom Views because whenever I press 1 or 2 on my keyboard for other things, I don’t want my view to change spontaneously.