https://learn.microsoft.com/en-us/azure/virtual-network/accelerated-networking-overview?tabs=redhat

For best results, enable Accelerated Networking on at least two VMs in the same Azure virtual network. This feature has minimal effect on latency when you communicate across virtual networks or connect on-premises.

You can't enable Accelerated Networking on a running VM. You can enable Accelerated Networking on a supported VM only when the VM is stopped and deallocated.