The approach to obtain input for gravitational-wave physics from scattering amplitudes in the Post-Minkowskian framework has been very successful in the past few years. For higher-order corrections vital for next-generation experiments, one of the main bottlenecks is the computation of multi-loop Feynman integrals. I will explain how to simplify the computation of these integrals by directly accessing the relevant classical contributions. Finally, I will discuss a concrete example on how scattering amplitudes can be used to compute observables including dissipative effects at O(G^3)