Your argument about low energy photons being capped at a black body level for heating is nonsense, a system can absorb all photons it can emit so typical matter

Your argument about low energy photons being capped at a black body level for heating is nonsense, a system can absorb all photons it can emit so typical matter can more or less absorb everything. Once energy from a photon has been absorbed it will diffuse in the material, increasing its temperature, energy quanta doesn't come into consideration here.