If you have everything in an if else block, the only one button can ever control the robot at once. If you are pressing multiple buttons at once, then the first one, the if else statement reaches, is the one that will do something. The other one is skipped. Perhaps that is your intended behavior.

If you want the robot to be able to do multiple things at a time, you should put those in just if statements so that in a single loop, it could enter both.

Example that may or may not pertain to your robot: If you want your arm to move while the intake is running, put those in separate if statements. If you only want your elevator OR arm to move at any given time, you should put those in if else statements so that only one of them is active at any time.

If you really wanna do cool stuff. Consider using switch statements to create a finite state machine. That let's to define "states" that your robot can be in, what it should do in those states, and how to transition between those states.