OP, I see from the example picture you posted, that you have some keybinds such as 9 or 0. Please tell me you have an MMO mouse and use the keys on the side for this, because if not those are some horrible keys to try and press (which would explain your issue with mobility). I'm 6'5 IRL and so I have massive hands, and even for me trying to press SHIFT-9 would be a task, especially when trying to move at the same time.

Personally, I use 12345ADRFXCV as my 12 binds as they're all within a single key's distance from my movement keys (QWES, I prefer left/right on Q/E so I don't have to move my fingers as far to reach the 12345 keys), then CTRL and SHIFT modified versions for two more hotbars. I have remapped the two side buttons on my mouse to act as CTRL and SHIFT, so I can easily press movement, a modifier key (using my mouse hand) and an actual keybind to do a spell/action, all at the same time. I'd recommend trying that out (if you have an MMO mouse disregard this)