I hear you, and our roadmap on Metal is something I want to be completely transparent about.
When I made the first forum post for PR1, Apple Silicon hadn't been announced yet nor made available for development work. Post M1, things are more complex in terms of keeping up support a decade of GPUs while also supporting this brand new architecture that is radically different (and also very promising). The Denoiser in particular had to be rewritten from scratch for M1, and the 2022 features will likely also require the minimum HW spec to move to 2020+ GPUs for latest features (including Brigade) to work.
With the next release of Octane X 2022 XB1, metal and CUDA releases going forward will be released in tandem. Octane X 2022 will primarily be optimized for native Apple Silicon - and as a head's up, by 2023 we may have to release features only for pre-Apple Silicon hardware as Apple's new GPU features and capabilities become supported only on Apple Silicon devices.