I talk to dev team leaders (EMs and PMs) multiple times a week about project management and it's quite rare that we find anyone using GitHub apart from very small teams (2-3 devs). Our research suggests product managers especially tend to prefer things like Notion/Trello and really don't like the complexity of GitHub.
Disclaimer: I'm a founder at Constructor (constructor.dev)
Disclaimer: I'm a founder at Constructor (constructor.dev)