multilingual websites example

Can anyone suggest me some sitemaps of multilingual websites that I can refer to?
My website has 5 languages, my team built it themselves, no WordPress and the sitemap is error leading to the website not being indexed at all.
I want to refer to some sitemaps of multilingual websites to see how they create sitemaps

Sitemap_index including each language sitemap should work. Check for /language/ on google and you will find examples.

I don’t think Nike uses Wordpress and I believe they have a very large multilingual site map: https://www.nike.com/sitemap-launch-index.xml

You could look at big multilingual websites like Wikipedia or Adobe to see how they organize their sitemaps. It might give you some ideas for fixing yours.