Using our Tilt buttons, you can be holding left or right and still get a neutral B. This allows for precise control of your turn around B in the air (no more accidental side-Bs!), as well as perfect positioning with your grounded B.
Both X1 and Tilt 2 are capable of this, and on our default layout each is accessible by one hand, so it's up to personal preference if you'd rather use one over the other, or both.
Our legacy video is a good overview of this, just remember X1 and Tilt 2 are the modifiers you want to use now: Tilt Neutral B - Smash Box SSBU.
Showcase of what you can do with Tilt Neutral Special in Ultimate, including B-Reverse and Wavebounces. More info: here.