A ready-to-use dependency, packing in the latest HarmonyX (and consequently MonoMod/Cecil) for other Gladio Mori mods to rely upon. Find it on mod.io here.
To use this pack, you'll need to add a reference to the nuget.org package ModioMori.HarmonyXPack. This package is solely a metapackage that keeps its runtime private, so HarmonyX will not be emitted when you build your mod. The runtime will be shipped by the HarmonyXPack game mod on mod.io, which requires a dependency added on mod.io.
The metapackage is targetted for .NET Framework 4.8.1. You should also target your mods for this framework version - it is the closest match to the version of Mono used by this game's Unity Engine version, and gives more APIs than targeting .NET Standard 2.1. Use LangVersion in your .csproj file to increase the C# version. You may need to add PolySharp for some modern features, but not most (up to C# 9 should work mostly perfectly without PolySharp).
Importantly, you must add this mod as a dependency to your gm.modcfg file and as a dependency on mod.io. If you are trying to use HarmonyX with a local (not published to mod.io) mod, you must build and package this yourself. This is because the game loads local mods before mod.io mods, so your load order will be wrong if you don't do this.
For an example group of package references in your .csproj:
<ItemGroup>
<PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.3" PrivateAssets="all" />
<PackageReference Include="ModioMori.HarmonyXPack" Version="2.16.0-p1" />
<PackageReference Include="UnityEngine.Modules" Version="6000.0.59" IncludeAssets="compile" />
</ItemGroup>For an example gm.modcfg:
{
"modioDependencies": [5585734]
}