The full default RPG maker controls are:
Move - Arrows
Action - z, enter, space
Cancel/Menu - x, num0, escape
Run - Shift
A,S,D,Q,W have functions assigned that are rarely used and C,V,B are unassigned but available in the rebinding menu.
In ARPGs made using RPG maker you typically see A used as the attack key by default so that it sits in the z,x,c a,s,d area for ease of use while block and special if featured will be between s, d or c.
Games of all types using arrow keys usually use 2 banks from q,w,e a,s,d z,x,c for the left hand or a line of 4-5 keys.
Its the same principle as modern strategy games often using a double bank of keys like qwer+asdf as hotkeys(on a qwerty layout) as opposed to the 90s system of using the first letter. Having the keys under 1 hand provides ease of use.
Since your setup overrides the player-end key rebinding menu (F1) I don't know whether having extra key options causes issues in your setup but if there isn't an issue adding back the key alternatives that were removed would make the game more approachable or as an alternative if you wanted to build on the WASD movement adding something like E as action and Q as cancel/menu would place the keys in a more comfortable location.
Adding back numpad0 as a cancel/menu button as a minimum would at least mean you have the full right hand key access in the sphere around the arrow keys.