Both devices, GPD-G5A and GPD-G7 have proper joystick drivers.
and yes, are based on PRO Controllers layout and specs.
6 button layout
2 button triggers (L1 & R1)
2 analog triggers (L2 & R2)
2 analog sticks (with good size)
sticks with buttons (L3 and R3)
D-PAD separated from sticks
buttons for android options (that we can use for other kind of tools, such tincore keymapper options)