: If Galadriel had given Feanor a lock of her hair when he begged her, would this have satisfied his desire for the Light of the Two Trees, therefore he wouldn't have made the Silmarils, which would have prevented the Revolt of the Noldor, the Ruin of Beleriand and the events leading up to the War of the Ruin etc.

The trees would have been destroyed in any case.
There would have been no Beleriand.
And somebody would have had to defeat Melkor in any case.
He would have destroyed Thingols realm because the Noldor wouldn't have been on the first line.