I suppose, although why is Zenject not allowed? Does it rely on pre-compiled libraries? I know even less about it than Bolt, but C# coding tools are generally fine. I mean, most of us use Rider or Visual Studio, rather than notepad or vim, because any tools that help coding easier is fine. But yeah, using actual code libraries or extra binaries is limited to Unity, packages from the Package Manager, and C# standard (can't remember which version Unity uses, I think it's C#v4).