I have read through the (numerous) posts about subnets - officially not supported by Roon, sadly - but I am quite confused about the current status. Some people have reported getting bits of this working by adding a second interface to their ROCK NUC; others have used mDns reflectors or other things at the network level; but much of the posted material is out of date or incomplete.
Our use case: The ROCK NUC, all players, and our home computers are on a single LAN. However guests (and our teenage son - who wants to trust a teenager’s cyber security? 
) are connected to a separate subnet with (just a little) firewalled access to the rest of our network.
We would like to give guests and son ability to control our Roon services and play music from their iPads/iPhones.
We run a Unifi Edgerouter Lite so could configure interesting things in the routing/firewalls if needed.
Anyone got a working solution to offer?