In the cycle under question (two DD reactions per D3He reaction), 91% of the fusion energy goes into charged nuclei, not into neutrons. In steady state where T is being allowed to decay into 3He and there's just one DD reaction, the fraction of energy in charged nuclei is even higher.

X-ray emission is strongly dependent on electron temperature. One of the important aspects of Helion's scheme is the electron temperature is much lower than the ion temperature. Not only does this greatly reduce x-ray emission, it reduces plasma pressure at a given ion temperature vs. a plasma where the ions and electrons are in thermal equilibrium, thereby increasing the ion density and fusion rate. The pulses in Helion's scheme end (and the plasma energy is recovered) before the electrons can heat up.