Hi @Anonymous Thank you for posting your Question on Microsoft Q&A.
Yes it is supported in SQL 2016 SP3. Below is the list of SQL releases that DNN is supported.
2019 CU8 and later
2017 CU25 and later
2016 Service Pack 3
Can we create DNN listener after installing SP3 on existing SQL 2016 Azure VM's?
Yes.
Configure DNN listener for availability group - SQL Server on Azure VM | Microsoft Learn
Hope that helps
Regards,
Oury