LyraStarterGame/Config/Custom/Steam/DefaultEngine.ini

[OnlineSubsystem]
DefaultPlatformService=Steam
bUseSteamNetworking=true

[OnlineSubsystemSteam]
bEnabled=true

[OnlineServices]
DefaultServices=Steam

[/Script/OnlineSubsystemUtils.OnlineEngineInterfaceImpl]
!CompatibleUniqueNetIdTypes=ClearArray
+CompatibleUniqueNetIdTypes=Steam

[/Script/Engine.Engine]
!NetDriverDefinitions=ClearArray
+NetDriverDefinitions=(DefName="GameNetDriver",DriverClassName="SteamSockets.SteamSocketsNetDriver",DriverClassNameFallback="OnlineSubsystemUtils.IpNetDriver")
+NetDriverDefinitions=(DefName="BeaconNetDriver",DriverClassName="SteamSockets.SteamSocketsNetDriver",DriverClassNameFallback="OnlineSubsystemUtils.IpNetDriver")
+NetDriverDefinitions=(DefName="DemoNetDriver",DriverClassName="/Script/Engine.DemoNetDriver",DriverClassNameFallback="/Script/Engine.DemoNetDriver")

[OnlineServices.Lobbies]
+SchemaDescriptors=(Id="GameLobby", ParentId="LobbyBase")
!SchemaCategoryAttributeDescriptors=ClearArray
+SchemaCategoryAttributeDescriptors=(SchemaId="LobbyBase", CategoryId="Lobby", AttributeIds=("SchemaCompatibilityId", "PRESENCESEARCH", "OSSv2"))
+SchemaCategoryAttributeDescriptors=(SchemaId="LobbyBase", CategoryId="LobbyMember")
+SchemaCategoryAttributeDescriptors=(SchemaId="GameLobby", CategoryId="Lobby", AttributeIds=("GAMEMODE", "MAPNAME", "MATCHTIMEOUT", "SESSIONTEMPLATENAME"))
+SchemaCategoryAttributeDescriptors=(SchemaId="GameLobby", CategoryId="LobbyMember", AttributeIds=("GAMEMODE"))
+SchemaAttributeDescriptors=(Id="SchemaCompatibilityId", Type="Int64", Flags=("Public", "SchemaCompatibilityId"))
+SchemaAttributeDescriptors=(Id="PRESENCESEARCH", Type="Bool", Flags=("Public", "Searchable"))
+SchemaAttributeDescriptors=(Id="GAMEMODE", Type="String", Flags=("Public"), MaxSize=64)
+SchemaAttributeDescriptors=(Id="MAPNAME", Type="String", Flags=("Public"), MaxSize=64)
+SchemaAttributeDescriptors=(Id="MATCHTIMEOUT", Type="Double", Flags=("Public"))
+SchemaAttributeDescriptors=(Id="SESSIONTEMPLATENAME", Type="String", Flags=("Public"), MaxSize=64)
+SchemaAttributeDescriptors=(Id="OSSv2", Type="Bool", Flags=("Public"))

[/Script/CommonUser.CommonUserBasicPresence]
bEnableSessionsBasedPresence=true
PresenceStatusInGame=Status_InGame
PresenceStatusMainMenu=Status_MainMenu
PresenceStatusMatchmaking=Status_Matchmaking
PresenceKeyGameMode=game_mode
PresenceKeyMapName=map_name

[/Script/CommonUser.CommonSessionSubsystem]
; SteamSocketsNetDriver does not support beacon connections at the moment, so the flow will be disabled in this platform
bUseBeacons=false