Status of the GCC/ARM_CM55 (and _NTZ) ports

I would need to refamiliarise myself to provide a complete answer, which I suspect Gaurav and Arm will be able to do sooner. Here are a couple of links to help:

The Cortex-M33 port also works on M55, explaining the similarity, but not explicit on additions required for MVE support - although I believe the vector registers alias onto the FPU registers

This commit (made by Arm) added M85 support. :

Blog with a link to a demo, also from Arm: Previewing the new Arm Corstone FreeRTOS Featured Reference Integration - FreeRTOS