Trying to color balance a composite

Hi, 
I'm a bit new to Photoshop 2022 and trying to do a composite edit of a cosplay.
I uploaded the photograph first then heal brush away imperfections on another layer. I then uploaded the background and free hand layer mask around the subject.
I am now trying to do a curve clip to make the subject match the color balance of the background but it keeps on going wrong.
I wonder if I have done something wrong or have to restart another way?
Any guidance would be much appreciated,

Josh (AsperJosh Photography)