Currently Microsoft SQL Server Always Distributed Availability Groups does not support one global listener for the entire distributed availability group. Replication technology is currently is configured using a single Listener, therefore until either Distributed Availability Groups support a single Listener or Replication support multiple Listeners, Distributed availability groups and Replication environments are not compatible.
When using transactional replication with Distributed availability groups the forwarder replica can’t be configured as a publisher.
If the goal is to move data to a distributed environment, consider using a Replication Re-Publisher topology. If need to support traditional replication subscriber activity, create SSIS job to READ changes from secondary replicas and write into a “downstream” replication publisher\distributor\subscriber topology.
Another option is to move the entire solution to Azure SQL Database distributed cloud-based solution providing both scale-out and scale-up capabilities.
Microsoft SQL Escalation Services