Zen is unlikely to ever have a patch for XIM APEX (they laughably think Zen is better for m/kb) and Zen is not capable of supporting 500 & 1000Hz Response Rates on XIM APEX because Zen's processing loop tops out at 4.5ms. Even 250ms is likely to cause sync issues given Zen's odd loop timing.
Titan Two has full support for XIM APEX at all Response Rates, as well as a bunch of other stuff Zen can't do like Computer Vision (search for XIM APEX vs Cronus Zen vs Titan Two).
XIM APEX simply plugs into Titan Two (or the other way around for expert-level stuff) and Titan Two into the console or computer. XIM handles the m/kb, Titan Two handles mods, macros and additional input devices e.g a wheel or HOTAS.
XIM APEX and Titan Two go hand in glove. Zen should not enter the conversation.