It has a snap declaration for ‘network-setup-observe’ already. My understanding was that netplan could hand off configuration to network-manager, but I was unaware that network-manager could configure netplan. I don’t see anything obvious in the network-manager sources on netplan support.
Can you provide more details on why network-manager needs to write netplan configuration?
network-manager needs to modify netplan files so it can set itself as the default renderer, otherwise netplan selects networkd as the default renderer for ethernet devices.