Hair is less manageable after highlights

Hi! I recently had highlights added to my hair, and I really like the overall effect - except now my hair has become a lot harder to style. It seems like the texture has changed to become more straw-like and it’s harder to brush through. When I add product (leave in cream or oil) it seems like it’s just sitting on top and making it greasy.

My hair is usually silky and soft - is there any way to get it back to that?

TIA!