> However the site got funding and started to focus on “diversity” and “inclusion” at all costs. Created a new CoC and the beginner content flooded in and has gone downhill since.

I was with you until that sentence. Focusing on “diversity” and “inclusion” or having a Code of Conduct with values like "Being respectful of differing viewpoints and experiences" is most likely not the reason for a community going downhill or beginner content flooding in.

The more likely reason is that the community became too big, the fluff posts from Medium shifted to other platforms and them not having a solid system for curating and surfacing interesting and valuable posts.