This seminar from the ICTP-SAIFR series features Maxence Corman from the Max Planck Institute, Germany, exploring the nonlinear dynamics of compact object mergers in theoretical frameworks that extend beyond General Relativity. Dive into advanced astrophysical concepts related to black hole and neutron star mergers, examining how alternative gravitational theories might affect merger dynamics and observable signatures. The presentation, delivered on May 16, 2025, offers nearly two hours of in-depth analysis of cutting-edge research in theoretical physics and astrophysics. Suitable for graduate students and researchers interested in gravitational physics, numerical relativity, and compact object astrophysics.