Hi @ozzy1986
If you enable the ‘show posts in the search results’ setting, it’ll generate the empty post sitemap, again?
You mentioned that you’ve also disabled your caching plugin. Were you able to check if the sitemap was cached elsewhere aside from your caching plugin – https://yoast.com/help/sitemap-does-not-update/
Often, we see problems occur in combination with another plugin or theme. The fastest way to rule out any conflict, is to deactivate all non-Yoast plugins and switch to a standard theme like Twenty Twenty.
Please test this on your development or staging site, if you have one. If not, we recommend using the Health Check & Troubleshooting plugin. This plugin has a troubleshooting mode, which does not affect normal visitors to your site.
If you’re unfamiliar with checking for conflicts, we’d like to point you to a step-by-step guide that will walk you through the process: How to check for plugin conflicts