Where do you put your thumb when you are using arrow keys? Maybe it's my small hands, but I can't use my right hand thumb to hit anything when I'm on arrow keys

Where do you put your thumb when you are using arrow keys? Maybe it's my small hands, but I can't use my right hand thumb to hit anything when I'm on arrow keys, and have to rely on using left hand to press modifiers. So, I use a keyboard with split space bars, and map the right one to a layer switch key, when I want arrow keys I then hold the right side spacebar, and use ijkl (similar shape to arrow keys). Feels like exactly the same [1] as using arrow keys except I don't have to move my hand. [1] Okay, 'I' is slightly off because row-staggered nonsense but honestly it just took me two days to get familiar to it.