Too much movement with the lower body tends to be common among golfers. It’s usually in an effort to generate more power in hopes of more distance. But in most cases the result instead is lack of balance, resulting in inconsistency.
To improve the consistency of solid shots, you need a solid base. Try making some practice swings without lifting your heel (or any other part of your foot) off the ground. The complete practice swing is flat-footed. This will keep you “swinging within yourself” and with the added stability your balance will be much better.
Once you have made a number of practice swings, hit some balls like this with a short iron. You’ll find that contact is crisper and more consistent. Work your way up to your driver using this drill. It will feel awkward at first but once you get used to it, you will like the feeling of balance and stability, not to mention the more consistent shots.