It can be difficult to hit small or thin targets precisely with the stylus, in any application. With a mouse or trackpad, the pointer is absolutely still if your hand is at rest, so it’s easier to make tiny adjustments with little nudges. In contrast, we can’t ever release the stylus, it needs to be held above the tablet instead of resting on it, otherwise the very sensitive stylus tip (desired for other uses) might register a click when you don’t want it to. This is a problem if the hand is unsteady.
Lightroom Classic can be especially challenging because it has some very tiny targets in the Develop panels, and some very thin lines to grab like adjusting the width of a panel, or grabbing a crop border. With the stylus, I have had to develop a habit of slowing down my hand as I bring the pointer close to a small target. That helps somewhat.
Another alternative you are already using is to have that mouse or trackpad available for highly precise moves. I have a trackpad to the left of the keyboard (tablet is on the right). I’ve gotten used to using the right hand for stylus actions, and the left hand for trackpad actions like fast scrolling, multi-touch shortcut gestures, precise adjustments, or keyboard shortcuts. Sometimes, when precise clicking is tricky, I’ll position with the stylus and use the trackpad to click, or just use the trackpad.
A third alternative is to use the Wacom tablet’s Precision Mode, where you get more control because the entire tablet area operates inside a small highlighted area of the screen. But that isn’t a great solution for cropping because you’d have to turn it on and off while in the middle of a crop drag, which almost certainly means you need to program it into one of the ExpressKeys and use your other hand to toggle that button while the first hand is dragging the stylus.
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