Which is better to style my hair to use serum alone or with mousse?

I'm a guy with short straight hair. I'm looking for kinda messy hairstyle with my hair being soft not hard.

Which is better to style my hair to use serum alone or with mousse?

I think mousse would give you more fluffiness where the serum will make it straighter.

Which is better to style my hair to use serum alone or with mousse?

have you tried both? do both and see which ones give u a better result