What program are you using that you are relying on Bezier curves for? When it comes to digital drawing, Beziers are for if you need a really precise curve for like a technical drawing and they kinda take time. I mean I got used to them back when I still used Illustrator, but Illustrator is not actually an Illustration program. Do you mean the drawing guides in Clip Studio?
What might help, if you find your curves are too shaky, is to apply more smoothing to your brush. In photoshop CC smoothing is a feature you can find in the toolbar, same in any version of Clip Studio (not sure about SAI or Procreate) I go the extra mile and I bought Lazy Nezumi, but I wouldn't dive into Lazy Nezumi unless you really need to since it's mostly for perspective guides and stuff (but it does have extra control over smoothing.)
Then these are kind of a shot in the dark easy tips you probably already know, but rotating your canvas so the angle of the curve matches your hand, drawing from your elbow and shoulder when doing big circular shapes, zooming in for trickier curves, and making sure you are using your whole tablet is pretty important for getting your speed up. (so if you use multiple monitors, make sure your tablet is only set for the monitor you're drawing on.) And also, random tip, but if you're doing a tricky line, always make sure you are breathing out. It keeps your hands from shaking. I actually do a little whistle when I have to do parallel lines, helps every time.