Whether a site uses http/https or www/non-www is not controlled in the Yoast SEO plugin. This is controlled in WordPress by the WordPress Address (URL) and Site Address (URL) values which are located in Settings>General. You would need to make sure that both of these are set to use HTTPS. If you are not seeing the site automatically use HTTPS in the URL after confirming these settings we would recommend checking with your host for more information on how to force all requests to the site to use HTTPS, as this can sometimes vary depending on the server configuration and hosting provider.
This issue can be caused if the site or server is caching the old version of the sitemap. We also have additional information on this at the following link: https://kb.yoast.com/kb/sitemap-does-not-update/. We would first recommend checking your caching settings and to ensure that the sitemap is being excluded from the cache. If you are still experiencing an issue with the sitemap not updating after checking your caching settings, you can also force a cache reset by temporarily disabling the sitemap feature, and then re-enabling. To do so please perform the following steps:
?In WordPress go to SEO>General>Features
?For ‘XML Sitemaps’ Toggle the switch to ‘Disabled.’
??Click ‘Save Changes.’
?Toggle the switch back to ‘Enabled.’
?Click ‘Save Changes.’
?We also have a guide on how to enable/disable XML Sitemaps here: https://kb.yoast.com/kb/enable-xml-sitemaps-in-the-wordpress-seo-plugin/
