How to make an object face the mouse in a non-2D world

I’m having trouble getting an object to rotate smoothly in a perfect circle.

This is my character in red. This is with a 3D camera in Orthographic view (with angles of (35,45,0)
I want the character to control as if the camera were placed directly above it, like any twin-stick shooter. If the mouse is in the top right, the character should face top right, if the mouse is in the top left, the character should face the top left (you get the idea)

This issue is that when mapping using things like the screen position on the mouse, the character will rotate fine if I only move the mouse left and right, or up and down, but if I use a combination of the two (such as when rotating in a clockwise motion around the character) it gets half way rotated before switching to rotate the other way (which is of course due to the x/y directions on screen becoming -/+)

Does anyone know a work around that will allow me to continue using this camera angle? I could easily do this if it were top down, but at this skewed angle I’m having trouble.

Any help will be greatly appreciated! Thank you!

You can do a raycast from your mouse to the ground plane you have and get the position of the hit point, and then you can simply to transform.lookAt at that point on the plane (assuming your character root is on the same level as the ground plane). Let me know if you want the code for this.