@Mandy_Kerr Great! I would recommend
@mpoppendieck's book "Lean Management" which
covers in great detail how to wholesomely approach KPIs for software teams:
https://coderbyheart.com/lean-mindset/

@romanpichler also has a nice article about
how to set goals:
https://www.romanpichler.com/blog/leading-through-shared-goals/