Is it possible to create a read-only federated community (only moderators can post and comment)?

I operate a content mirroring instance that is intended to be read-only, where only a moderator bot is allowed to post and comment. However, I realized that comments can still be made on posts even when the community is set to "Only moderators can post". Locking threads can block comments but it would also prevent the bot from posting comments, and there are a lot of threads to lock.

My naive solution is currently to ban anyone who comments, but is there any better way to create a read-only community without also blocking federation?