On my opinion, if Google isn't updating your sitemap and the "last read date" isn't changing, try fixing any errors in your sitemap, make sure Google can access it, and improve your website's content and structure to encourage more frequent updates by Google.Google does not read the site map.
Even if I resubmit the update, the "last read date" will not be updated.
Is there a way to solve this?
All other pages except the Administrator Bulletin are robot.txt so that they are accessible.Are you sure there is nothing blocking access to .xml files on your server? Robots.txt, .htaccess rules, Cloudflare rules etc.
All other pages except the Administrator Bulletin are robot.txt so that they are accessible.review your robots.txt file to ensure that it is not preventing Google from accessing and reading your website. Once you've confirmed this, double-check and then resubmit it in Google Search Console.
All other pages except the Administrator Bulletin are robot.txt so that they are accessible.Ensure your sitemap is correctly formatted and robots.txt doesn't block it.