I think moving AG is not possible unless you will edit configuration files and auth files. I'd recommend install a fresh activegate for the new cluster and point all agents to the new endpoint using oneagent CLI
Actually, if the host itself does not change, you can easily just uninstall the old ActiveGate and install a new one from the new environment on the same host.
By an in-place reinstallation you shouldn't need to point OneAgents to a new location and they will automatically try to connect to the new gateway. But OneAgents will need to have the token and environment ID updated anyway.