Google Search Console is the best tool to check and validate XML Sitemaps if you have access to it. However, you can check the errors only after submitting the XML Sitemaps. If you want to validate them before submitting them to Google, you have to use other free online tools. There are a few famous tools you can check. All the URLs shared by other members are no longer available except this. https://xmlsitemaps.app/xml-sitemap-validator.html