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

src/NadekoBot/Modules/Utility/Alias/AliasService.cs

@@ -0,0 +1,95 @@
+#nullable disable
+using Microsoft.EntityFrameworkCore;
+using NadekoBot.Common.ModuleBehaviors;
+using NadekoBot.Db;
+using Nadeko.Bot.Db.Models;
+
+namespace NadekoBot.Modules.Utility.Services;
+
+public class AliasService : IInputTransformer, INService
+{
+    public ConcurrentDictionary<ulong, ConcurrentDictionary<string, string>> AliasMaps { get; } = new();
+    private readonly IEmbedBuilderService _eb;
+
+    private readonly DbService _db;
+
+    public AliasService(DiscordSocketClient client, DbService db, IEmbedBuilderService eb)
+    {
+        _eb = eb;
+
+        using var uow = db.GetDbContext();
+        var guildIds = client.Guilds.Select(x => x.Id).ToList();
+        var configs = uow.Set<GuildConfig>()
+                         .Include(gc => gc.CommandAliases)
+                         .Where(x => guildIds.Contains(x.GuildId))
+                         .ToList();
+
+        AliasMaps = new(configs.ToDictionary(x => x.GuildId,
+            x => new ConcurrentDictionary<string, string>(x.CommandAliases.DistinctBy(ca => ca.Trigger)
+                                                           .ToDictionary(ca => ca.Trigger, ca => ca.Mapping),
+                StringComparer.OrdinalIgnoreCase)));
+
+        _db = db;
+    }
+
+    public int ClearAliases(ulong guildId)
+    {
+        AliasMaps.TryRemove(guildId, out _);
+
+        int count;
+        using var uow = _db.GetDbContext();
+        var gc = uow.GuildConfigsForId(guildId, set => set.Include(x => x.CommandAliases));
+        count = gc.CommandAliases.Count;
+        gc.CommandAliases.Clear();
+        uow.SaveChanges();
+        return count;
+    }
+
+    public async Task<string> TransformInput(
+        IGuild guild,
+        IMessageChannel channel,
+        IUser user,
+        string input)
+    {
+        if (guild is null || string.IsNullOrWhiteSpace(input))
+            return null;
+        
+        if (AliasMaps.TryGetValue(guild.Id, out var maps))
+        {
+            string newInput = null;
+            foreach (var (k, v) in maps)
+            {
+                if (string.Equals(input, k, StringComparison.OrdinalIgnoreCase))
+                {
+                    newInput = v;
+                }
+                else if (input.StartsWith(k + ' ', StringComparison.OrdinalIgnoreCase))
+                {
+                    if (v.Contains("%target%"))
+                        newInput = v.Replace("%target%", input[k.Length..]);
+                    else
+                        newInput = v + ' ' + input[k.Length..];
+                }
+
+                if (newInput is not null)
+                {
+                    try
+                    {
+                        var toDelete = await channel.SendConfirmAsync(_eb, $"{input} => {newInput}");
+                        toDelete.DeleteAfter(1.5f);
+                    }
+                    catch
+                    {
+                        // ignored
+                    }
+
+                    return newInput;
+                }
+            }
+
+            return null;
+        }
+
+        return null;
+    }
+}