Restructured the project structure back to the way it was, there's no reasonable way to split the modules

src/NadekoBot/Modules/Administration/GameVoiceChannel/GameVoiceChannelCommands.cs

@@ -0,0 +1,36 @@
+#nullable disable
+using NadekoBot.Modules.Administration.Services;
+
+namespace NadekoBot.Modules.Administration;
+
+public partial class Administration
+{
+    [Group]
+    public partial class GameVoiceChannelCommands : NadekoModule<GameVoiceChannelService>
+    {
+        [Cmd]
+        [RequireContext(ContextType.Guild)]
+        [UserPerm(GuildPerm.Administrator)]
+        [BotPerm(GuildPerm.MoveMembers)]
+        public async Task GameVoiceChannel()
+        {
+            var vch = ((IGuildUser)ctx.User).VoiceChannel;
+
+            if (vch is null)
+            {
+                await ReplyErrorLocalizedAsync(strs.not_in_voice);
+                return;
+            }
+
+            var id = _service.ToggleGameVoiceChannel(ctx.Guild.Id, vch.Id);
+
+            if (id is null)
+                await ReplyConfirmLocalizedAsync(strs.gvc_disabled);
+            else
+            {
+                _service.GameVoiceChannels.Add(vch.Id);
+                await ReplyConfirmLocalizedAsync(strs.gvc_enabled(Format.Bold(vch.Name)));
+            }
+        }
+    }
+}

src/NadekoBot/Modules/Administration/GameVoiceChannel/GameVoiceChannelService.cs

@@ -0,0 +1,127 @@
+#nullable disable
+using NadekoBot.Db;
+
+namespace NadekoBot.Modules.Administration.Services;
+
+public class GameVoiceChannelService : INService
+{
+    public ConcurrentHashSet<ulong> GameVoiceChannels { get; }
+
+    private readonly DbService _db;
+    private readonly DiscordSocketClient _client;
+
+    public GameVoiceChannelService(DiscordSocketClient client, DbService db, IBot bot)
+    {
+        _db = db;
+        _client = client;
+
+        GameVoiceChannels = new(bot.AllGuildConfigs
+                                   .Where(gc => gc.GameVoiceChannel is not null)
+                                   .Select(gc => gc.GameVoiceChannel!.Value));
+
+        _client.UserVoiceStateUpdated += OnUserVoiceStateUpdated;
+        _client.PresenceUpdated += OnPresenceUpdate;
+    }
+
+    private Task OnPresenceUpdate(SocketUser socketUser, SocketPresence before, SocketPresence after)
+    {
+        _ = Task.Run(async () =>
+        {
+            try
+            {
+                if (socketUser is not SocketGuildUser newUser)
+                    return;
+                // if the user is in the voice channel and that voice channel is gvc
+
+                if (newUser.VoiceChannel is not { } vc
+                    || !GameVoiceChannels.Contains(vc.Id))
+                    return;
+
+                //if the activity has changed, and is a playi1ng activity
+                foreach (var activity in after.Activities)
+                {
+                    if (activity is { Type: ActivityType.Playing })
+                        //trigger gvc
+                    {
+                        if (await TriggerGvc(newUser, activity.Name))
+                            return;
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                Log.Warning(ex, "Error running GuildMemberUpdated in gvc");
+            }
+        });
+        return Task.CompletedTask;
+    }
+
+    public ulong? ToggleGameVoiceChannel(ulong guildId, ulong vchId)
+    {
+        ulong? id;
+        using var uow = _db.GetDbContext();
+        var gc = uow.GuildConfigsForId(guildId, set => set);
+
+        if (gc.GameVoiceChannel == vchId)
+        {
+            GameVoiceChannels.TryRemove(vchId);
+            id = gc.GameVoiceChannel = null;
+        }
+        else
+        {
+            if (gc.GameVoiceChannel is not null)
+                GameVoiceChannels.TryRemove(gc.GameVoiceChannel.Value);
+            GameVoiceChannels.Add(vchId);
+            id = gc.GameVoiceChannel = vchId;
+        }
+
+        uow.SaveChanges();
+        return id;
+    }
+
+    private Task OnUserVoiceStateUpdated(SocketUser usr, SocketVoiceState oldState, SocketVoiceState newState)
+    {
+        _ = Task.Run(async () =>
+        {
+            try
+            {
+                if (usr is not SocketGuildUser gUser)
+                    return;
+
+                if (newState.VoiceChannel is null)
+                    return;
+
+                if (!GameVoiceChannels.Contains(newState.VoiceChannel.Id))
+                    return;
+
+                foreach (var game in gUser.Activities.Select(x => x.Name))
+                {
+                    if (await TriggerGvc(gUser, game))
+                        return;
+                }
+            }
+            catch (Exception ex)
+            {
+                Log.Warning(ex, "Error running VoiceStateUpdate in gvc");
+            }
+        });
+
+        return Task.CompletedTask;
+    }
+
+    private async Task<bool> TriggerGvc(SocketGuildUser gUser, string game)
+    {
+        if (string.IsNullOrWhiteSpace(game))
+            return false;
+
+        game = game.TrimTo(50)!.ToLowerInvariant();
+        var vch = gUser.Guild.VoiceChannels.FirstOrDefault(x => x.Name.ToLowerInvariant() == game);
+
+        if (vch is null)
+            return false;
+
+        await Task.Delay(1000);
+        await gUser.ModifyAsync(gu => gu.Channel = vch);
+        return true;
+    }
+}