Shifting from GitHub Issues as the default project management is a good prime candidate for starting to move the needle. Public-facing Clubhouse-the-project-management-app would be easier for non-eng contributions, holding open OKR processes, and having some clear ways for non developers to contribute.
Fwiw I tried to help on growth / product on one consumer OSS product I love- there just wasn’t a mechanism for someone to say yes, and there was a need for centralization to do some of the obvious next practices any startup would do. It’s easy for engineers to contribute, but ambient hostility and concern about marketing / growth / product tactics make it tough to turn rock solid OSS technology into competitive OSS products.