Hello!
I think it would be a good idea to make community posts exclusive to communities. The fact that all community posts can be seen on your profile anyway, doesn't really give incentive for people to really check out a community you've created because there's no need for it. Making it exclusive would encourage someone to join a group. Similar to how groups are managed on other social media platforms, like Facebook for example.
I think it could also reduce annoying popups for people who aren't a part of the community and don't care for constant notifications.
I think such a feature would really benefit communities and make it really feel like its own special group. That way the members who joined are really there to interact with the group.
Thank you!