can I fix liquid damage on mac air M3 without repairing?

I accidentally spilled a small amount of milk on the left corner of my Mac. I took it to an Apple technician, and they checked for liquid damage. They said it was minimal and barely noticeable. There's no visible liquid on the screen.However, I'm now experiencing two issues 1 Occasionally, the brightness gets stuck, and I can't adjust it (specifically on the side where the spill happened). I have to restart the Mac to fix it 2 Since yesterday, I've had trouble turning the Mac on—it sometimes goes dark. The technician mentioned it needs repairs, which would cost $299 (I have AppleCare). They also emphasized that the liquid damage is very minor. Is there any way to work around these issues without going through the repair process?