What community posts are good for
Videos take days or weeks to make. Posts take minutes, and they keep your channel in front of subscribers between uploads.
The posts that work best ask something of the viewer: vote in a poll, answer a question, guess what is coming next. The answers also tell you what your audience wants from the next video.
Announcements work too, such as a new video, a schedule change or a livestream time, but a channel that only announces gives viewers no reason to engage with the post itself.
Three post types to rotate
Each run gives you three angles on your topic: a story or update, a tip, and a question.
The update is the behind-the-scenes post: what you are filming, what went wrong, what you learned. The tip post gives one useful thing from your niche, a small sample of what your videos teach. The question post invites comments and pairs well with a poll.
Rotate them through the week and the Posts tab becomes a reason to visit your channel even when there is no new video.