Google Sitemap Troubleshooting for WordPress

I'm facing a critical issue with my WordPress site. My Google Sitemap is not being found, causing significant SEO concerns. I have attempted to use various plugins to generate the sitemap, but unfortunately, none have worked.

I need a professional with:
- Deep understanding of WordPress and its plugins
- Proven experience in debugging Google Sitemap issues
- Strong SEO background
- Ability to provide a reliable solution

Please reach out if you can help me restore my site's visibility on Google.