two windows use two arrow key

I have an idea, I hope to have two windows side by side on the screen, for example evince on the left and gedit on the right. I hope that Fn+WASD can move the cursor in evince, and Fn+IJKL can move the cursor in gedit. When I type normally, the input content is displayed in gedit. How can I do this? Currently I use linux mint 21.3. Or replace the above Fn+WASD with Win+WASD/LAlt+WASD