Need some help with wall patch
Part of the problem may be sanding technique. It appears that you have used a soft pad or bare sheet. You need to use a rigid block to prevent sinking into soft spots.

Apply another coat of patch material, and taper it out a bit further. Proper drywall work doesn't involve much sanding at all, so make sure to use a wide knife or trowel at a low angle to create a flat, smooth repair. Sanding should take mere seconds.