If I were to guess what actually fixed my issue (I did add a few changes from your example but this one was the most significant I think.)
+NetDriverDefinitions=(DefName=“GameNetDriver”,DriverClassName=“/Script/SteamSockets.SteamSocketsNetDriver”,DriverClassNameFallback=“/Script/SteamSockets.SteamNetSocketsNetDriver”)
as opposed to…
;+NetDriverDefinitions=(DefName=“GameNetDriver”,DriverClassName=“OnlineSubsystemSteam.SteamNetDriver”,DriverClassNameFallback=“OnlineSubsystemUtils.IpNetDriver”)
I did get it working and was able to create/join games with my Lyra example through Steam. I’d like to note though that there seems to be a bug with 5.1 that causes the server to refuse packets from the client sometimes. I can’t reproduce it all the time but you’ll see it in the console output on the server side if it can’t verify the packets.
One last note, “bUseLobbiesIfAvailable = false” I noted could also have something to do with me being able to get joining games working properly- but that stuff comes after Steam Sockets are fixed and the server can create a game properly.