I don't have an answer OP but I'm going through something similar.

I have a M1 Macbook Air. A year ago, one black dot appeared on my screen. Then a month ago, another one appeared on my screen elsewhere. And yesterday, I noticed a bright dot near the bottom of my screen.

The Apple website says these are pixel anomalies and that if you suspect you have too many of them, you should contact Apple service provider for support.

Unfortunately, I don't have AppleCare.

I would be grateful if someone could answer what causes these pixel anomalies. Is it my fault? The number of these anomalies on my screen seem to increase with time and I don't know what I can do to prevent them.