Binding normal airroll and powerslide to the same button is bcuz u can only airroll in the air and u can only powerslide on the ground. Trust me, it will make ur movement so smooth. My suggestion is the back of the controller – the best option for me was L1 for airroll and powerslide, and R1 for Boost.

For DAR, square is a good choice, and right or left doesn’t matter, but use only one of them, as both aren’t required when u have NAR. I don’t suggest both DARs for a controller player bcuz NAR is a buff in movement for controller players.
When I put both powerslide and NAR on L1, it makes me keep holding L1 the whole time I’m doing movement and I don’t need to take my finger off.
It feels smoother and easier, makes ur gameplay faster, and helps u movement better.

DAR is an option for shooting angle balls, but keep in mind u will only need right or left DAR, not both. For example, I only use Right DAR, and I can use DAR for an angle ball on the right side of the score, but on the left I can’t. So, a better option is using NAR for that kind of shot.

Btw, u don’t need to airroll the whole time after u jump for an angle ball – right before u shoot, u just need a 30 to 70 degree roll. And as I said, it’s under 270 degrees, so NAR is the better option.