During prayer, I bent down for rukoo, but realised I forgot qunoot and went back up. Then rukoo again.
I know qunoot isn’t mandatory, but I did this automatically without much thought.

Did I invalidate salah with two rukoo? I did not say any dhikr in first rukoo

Your namaz is batil

Ruling 1025. If a person intentionally raises his head after reaching the position of rukūʿ, and again bends forward to the extent of rukūʿ, his prayer is invalid.