The Quark-Gluon Plasma is the deconfined phase of QCD matter at extreme temperatures and densities. The Universe was in these conditions just a few microseconds after the Big Bang, while today one can realize them in two situations: on earth, in ultrarelativistic heavy-ion collision experiments at RHIC and the LHC, and in the core of compact stellar objects and their mergers. The first gravitational wave observations from the LIGO/VIRGO collaboration have opened a new field of research, through which a mapping of the phase diagram of strong interactions can be achieved for the first time. The future Cosmic Explorer and Einstein Telescope will be able to detect the ringdown signal, which is very sensitive to the dense matter Equation of State. This project provides first principle and phenomenological results for the heavy-ion community, by calculating relevant observables such as constraints on the location of the QCD critical point, the QCD equation of state in phenomenologically relevant but so-far unexplored settings, and a time-dependent jet quenching parameter. At the same time, it builds a bridge to the astrophysics community, by providing observables that will allow more stringent constraints on high-density phenomenological models. The project will also contribute to training the next generation of students who work on the theory of fundamental interactions, both at the undergraduate and graduate levels. The purpose of this project is to improve the understanding