My instructor showed me this thing where I would tie my stirrup to my girth with bailing twine quite tightly so my stirrup wouldn't move. It's really good cause it keeps you're leg still and it also keeps your toes in. It hurt a bit the first few times because I wasn't used to having my leg in the correct position but I did it for about 2 weeks every time I rode (I probably wouldn't recommend jumping with it though) and I really noticed a difference after.
No stirrups or you can try riding with Long stirrups for two weeks and then short stirrups for the next two weeks
Besides riding bareback/ with no stirrups, you should also check if your leg is being properly supported by your saddle, if not look into some saddle rolls, they're fantastic!
To keep your hands still try and make sure that you are relaxed through your elbow when you ride. When I was to active with my hands my coach used to put a strap on the saddle where you can also attach breastplates and she would make me grab the strap whenever I started fidgiting. It helped a lot!
try riding bareback or ride with no stirrups. For your hands think about it this way: your body should be moving not your arms. When you're posting (trotting) move your body toward your hand, not the other way round. But also remember to relax. If you have a trainer you should ask for help to your trainer. I wish you luck on your riding! :)
Maybe try no stirrup riding i find it helps alot and you still have support unlike bareback riding (which is also good)