Ancient Bracelet

Both dramas have an object that allows the characters to turn back time (flute vs. bracelet). Both have non linear time travel, with the FL as a child in ML's time and her traveling back as an adult to meet him. Both leads have a relationship that shifts from antagonistic and harming each other to devoted and deeply sacrificial.

Both dramas have the FL meeting the ML as a child, something one of the leads is unaware of/has forgotten due to non linear time travel/etc. Both dramas are xianxias.