This is a great concrete example because it gets to a point where "Zenoh runs on microcontrollers" needs some unpacking. The interesting question is not whether Zenoh can run on an MCU, but where you put the Zenoh endpoint and how you bridge between your real-time application core and the networking core.
Your MCXN947 scenario is actually very similar to architectures used in industrial MCUs and heterogeneous SoCs:
MCU
+--------------------------------+
| |
| Core 1 | Core 0
| (application) | (communications)