Email from Samung this week. They are killing off the Linux on Dex project, with the release of Android 10 on their phones. 🙁 Text from announcement in link below.
http://www.tuxmachines.org/node/129474#comment-22115
Bit miffed as I do tinker with it on and off.
@DirtyDean
I only have the note8, which was just a generation too old to support DeX.
Although my SO does have the note9, this just means we will not be a DeX household ;)