Action to post an issue to Slack daily

Have been looking around but not really finding something to do what I am hoping to.

I am looking for a way to have an issue posted to Slack daily, for example an oncall report where all the content is in the main post and not the comments, and I would like to be able to grab that and have it posted to a slack channel each morning.

This sounds like a good use case for a workflow with an on: schedule trigger. You can have it run daily, query the GitHub API e.g. via actions/github-script for new issues, and then use an existing Slack notification action from the marketplace to post you this information.