We study the interplay between non-Hermitian dynamics and phase synchronization in a system of N bosonic modes coupled to an auxiliary mode. The linearity of the evolution in such a system allows for the derivation of fully analytical results for synchronization conditions. In contrast, analysis at the level of phase dynamics, followed by a transformation to a collective basis allows a complete reduction to an all-to-all coupled Kuramoto model with known analytical solutions. We provide analytical and numerical solutions for systems ranging from a few modes to the macroscopic limit of large N in the presence of inhomogeneous frequency broadening and test the robustness of phase synchronization under the action of external noise
