There are whole university degrees about "physics of complex systems". "Emergent properties" is a lens you use when looking at something. For example magnetism is seen as an emergent property of particles interacting and aligning. Thermodynamics can be seen as emergent properties of statistical mechanics (pressure, temperature etc). Agency is another example of lenses used to interpret something. Does a toaster have agency because it's trying to toast bread? Yes or no depending on the lenses you are using to describe its behaviour.