Galaxy clusters provide rich astrophysical laboratories, enabling studies of the most energetic events since the Big Bang. The myriad of important astrophysical phenomena present in high energy events such as galaxy mergers and active galactic nuclei, include shocks, cold fronts, and interactions of gas within the envelope of the cluster’s dark matter potential. The study of galaxy cluster physics yields a fundamentally unique opportunity to probe the properties of cluster dynamics and the intracluster medium (ICM). High-resolution observations of pressure substructure in the ICM with the second generation Multiplexed SQUID/TES Array at Ninety GHz (MUSTANG-2) provide a powerful probe into the dynamical state of these clusters.MUSTANG-2 contains a 223-pixel bolometer array with a microwave SQUID multiplexed ($\mu$MUX) readout system, which combines the sensitivity of TES detectors with the multiplexing capability of Microwave Kinetic Inductance Detectors (MKIDs). The $\mu$MUX readout system has been demonstrated to multiplex 400 bolometers with no degradation in noise performance. Arrays of thousands of polarization sensitive TES detectors can be read out on a single feedline by tuning each SQUID on the $\mu$MUX to a slightly different resonance frequency. Thousands of resonators can be fabricated onto a single layer, coupled to one feedline and then amplified by a cryogenic HEMT amplifier. MUSTANG-2 will not only dramatically aid in increasing our understanding of high-energy astrophysical phenomena and their relationship to cosmological parameters, but also significantly advance the technology readiness level of highly multiplexed detector arrays.