Old Sitemap.xml is stuck in cache

I did some research but couldn’t find a solution. I used Yoast to generate the sitemaps. I had to change permalinks across the site and re-direct the pages to the new ones.

I deleted the sitemap.xml in the Google Console and added the new sitemap. My problem is, the new sitemap still contains the old URLs! I cleared the cache but I can’t get rid of the old sitemaps within WordPress.

I had to use an external sitemap generator to create the latest sitemap.

Any ideas?