Currently we only see a option for configuring a mongo remote instance. do we have an option to configure mongo remote atlas cluster ?
You should use a PMM client to connect to it. From the docs, you may need to use the following additional argument when adding it:
Atlas doesn’t support direct connections. When connecting to an Atlas instance, use the pmm-admin option --direct-connection=false. (Doing so will prevent replicaset status from working and the MongoDB Overview dashboard widget will show invalid values.)