winrt::hresult_class_not_registered - AudioEffectDefinition with custom effect

I'm trying to create a winrt custom audio effect using this tutorial.
#include "MyAudioEffect.g.h"

auto effectName = winrt::name_of();
auto effect = winrt::Windows::Media::Effects::AudioEffectDefinition(effectName);
// Exception thrown
// winrt::hresult_class_not_registered
// 80040154 - Class not registered



I made a MRE:
https://github.com/tom-huntington/MRE_ClassNotRegistered />

To create the .idl .h .cpp files for the MyAudioEffect class, I used the template
-> Add -> New Item -> Custom Control (WinUI 3)



How do I register the class? Can someone fix my MRE please?