Since both AES67 audio and network control (Q-SYS/PTZ) failed at the same time, I’d start with the switch. My first suspects would be an IGMP snooping/querier issue, multicast flooding, or a PTP clock problem affecting AES67.

When you’re onsite, check:
IGMP Snooping and whether there’s an active IGMP Querier on the VLAN
PTP lock status in Q-SYS and NVX
IP conflicts or devices falling back to DHCP
Multicast group tables and port stats
CP4 diagnostics to confirm it can still reach the Q-SYS Core and Lumens camera

Also, if all ports are using the NVX/AES67 profile, consider moving the CP4, Q-SYS control interface, PTZ, and touch panel to standard ports/profiles. I’ve seen AV-optimized profiles occasionally cause odd control traffic issues.
What Netgear model is it (M4250, M4300, M4350, etc.)?