Men seem to like women with light hair because they think they look "younger". There are even some studies that support this observation.

https://www.tandfonline.com/doi/abs/10.1080/00224545.2017.1395791

I am a brunette and I received more attention back when I had dyed my hair red. I don't think I even looked very good with red hair, I actually looked pretty trashy, but still.

Dyeing your hair a light color is usually a good strategy. Mark my words.