This work explores the phenomenological consequences and falsifiable predictions of the MyominAung Photon-Sea Theory (MATE), a nonlinear field framework characterized by an inverse mass–frequency relation. The theory predicts observable deviations from standard models across multiple experimental and observational domains, including atomic clock precision measurements, weak-field gravity tests, gravitational wave ringdown spectra, and late-time cosmology. In particular, low-frequency saturation effects give rise to emergent gravitational behavior, smooth dark-matter–like dynamics, and cosmic acceleration without invoking new particles or a cosmological constant. Clear falsification criteria are identified, establishing concrete pathways through which current and next-generation experiments can test or rule out the framework. These results position MATE as a minimal and empirically accessible alternative approach to unification and cosmological phenomenology.