I am absolutely thrilled that the Colombian peace accords have been renegotiated, and that the differential approach in it is stronger than before. I continue to see the false cognate focus widely used in the media (which is one part of the broader enfoque diferencial in the accords, which now clearly include age, gender, sexual orientation, gender identity, religion, and ethnicity).
The term enfoque diferencial is fairly new, but enfoque de género is a term widely used in multilateral treaties and agreements. Gender approach is the standard UN and EU translation. A good tool for finding these is what used to be called the eurodicautom and is now, sadly, called iate.
As for the term differential vs differentiated, I have spent way too much time obsessing over the difference. The Real Academia defines diferencial as
1. adj. Perteneciente o relativo a la diferencia entre las cosas. Un estudio diferencial.
2. adj. Que diferencia o sirve para diferenciar. Caracteres, matices diferenciales.
I believe that it's this second definition that is at work in this term. I was utterly convinced that differentiated conveyed that meaning more clearly in English, but I have come around. It is not un enfoque diferenciado, but actually uno diferencial. It may not be a term in as common use in English as in Spanish, but it does exist. Merriam-Webster gives the simple definition of differential as
relating to or based on a difference : treating some people or groups differently from others.
Their full definition is:
1 a : of, relating to, or constituting a difference : distinguishing b : making a distinction between individuals or classes c : based on or resulting from a differential d : functioning or proceeding differently or at a different rate
2 : being, relating to, or involving a differential or differentiation
3 a : relating to quantitative differences b : producing effects by reason of quantitative differences