Our next aim is to extend the results of Chapter 2 and introduce a notion of weak solution to gradient flows in metric measure spaces in a fairly general setting. Our main assumption is that the functional only depends on the differential of a function. In particular, this setting covers the case when the functional only depends on the function through its minimal p-weak upper gradient. In this entire chapter, we assume that p > 1 and that we work with a convex and lower semicontinuous functional defined on L2, which is given by a composition of the differential and a non-negative, continuous, convex, and coercive functional defined on the cotangent space. We first present the general framework under the minimal structural assumptions described above. Then, we apply the newly developed techniques to study a specific functional with inhomogeneous growth, which is the sum of two Cheeger energies for different exponents.