Is the wrong version installed? Run npm i --production to ensure the proper composer version is installed.
Otherwise, perhaps the issue has been fixed in a newer version of NodeBB... what commit are you on?
When we used to use IPB, we had a handy feature where general public members could enter a forum and only see the topics they have created themselves (used to be handy with ban appeals and reporting people without judgement)
Is there a way we can do this with NodeBB?
Not at the moment without a custom plugin.