There is NO "requirement" for notarization. This FUD keeps getting perpetuated, but you can publish macOS software without paying $99 year.
> It should be possible to verify developers and distribute open source apps without a cost on macOS.
The cost is convincing your users to trust you and allow your unsigned app to bypass Gatekeeper.
I've seen some tools do just that, explaining that they cannot afford the notarization fee.