All formats limit a single sitemap to 50MB (uncompressed) and 50,000 URLs. If you have a larger file or more URLs, you will have to break your list into multiple sitemaps. You can optionally create a sitemap index file (a file that points to a list of sitemaps) and submit that single index file to Google. You can submit multiple sitemaps and/or sitemap index files to Google.
Notes
Resources
https://hyku.samvera.org/2017/06/22/resourcesync.html https://support.google.com/webmasters/answer/183668?hl=en