Is it possible to make a standard, pre-existing, teams channel read-only?

I have a pre-existing standard teams channel that I want to update to read-only status so that the conversations can be reviewed as a resource, while preventing any new posts or replies.

The post content has extreme value and needs to be accessible for reference only.

While moderator prevents replies, it does not prevent new posts.

Is the functionality available and I just cannot see it?  Or is this simply not possible? In other words, could I contact my IT and ask them to enable this function.