DNNs are supported as of SQL Server 2019 CU2 and require Windows Server 2016 or later. I wrote more about them in my blog post Configure a WSFC in Azure with Windows Server 2019 for AGs and FCIs. Go there if you want to see what they look like and learn more.
Right now, I cannot wholeheartedly recommend the use of DNNs for listeners or FCIs if you are using Enterprise Edition. Why?
Read on to learn why.