After upgrading to version 1809 I experienced the same issue with discovery of other Windows 10 PC's and shared files. I became aware of a 'new feature' in Windows 10 ( after a through review of all items in the 'Setting Menu's' ) which became available in 1803 but wasn't really hilite'd enough by Microsoft or the press. Windows Settings/System/Shared Experience/Nearby Sharing using WiFi. Once turning on Nearby devices (my devices only) my sharing desktop PC and it's shared drive and folder became immediately discoverable by my other PC's on my network.
This looks to be Microsoft's replacement for 'Homegroup'
Well I couldn't even try this if I wanted to. I took a look at my computers and even though they are all configured the same one doesn't even have this "Nearby sharing" option under "Shared Experiences", it only has the second option, "Share across devices". What kind of garbage is that?
I am so over Windows and its constant issues. So sorry I got in bed with MS years ago when I purchased my first PC. If I had bought a Mac I would have never looked back.