my suggestion would be to make the movement to be based on the perspective
Rn (based on perspective)
W moves the char in the top left dir
S moves him in the bottom right dir
A moves him in the bottom left dir
And D to the top right
This makes sense if you look at it from a top down angle but from this orthagonal perspective it feels a bit off
Tbh ive never really worked on a game with this perspective so i cant advice on how to fix it, but maybe you can look up some tutorials on player movement for this perspective
I hope this helps
If you update it and want someone to test it, ill definitely be down to give it another go :D