XML sitemap on subdomain?

I just launched a new product on a "young" platform, they still haven't developed an XML sitemap. My question is if anyone has experience or tried hosting a sitemap on a subdomain (different server), if that affects the results or if is worth the afford?

So I would host the main sitemap on the main domain like this
https://domain.com/sitemap.xml

<loc>https://map.domain.com/sitemap1.xml</loc>
<lastmod>2019-06-18</lastmod>
</sitemap>
<sitemap>
<loc>https://map.domain.com/sitemap2.xml</loc>
<lastmod>2019-06-18</lastmod>
</sitemap>

my site is showing real-time events so they need to be updated daily

any thoughts?

I think you can submit that sitemap to google as long as it is the same domain. Google might ask you to verify both domain and subdomain in order to submit sitemap though. After you verify just submit it from webmaster tools.

because it's in the same domain, just a different subdomain, should be OK right? I never did it like this before because in no scenario you should have to. Ok, will try and see...

Is there a reason why would you think that it is not useful to have a sitemap on a subdomain (subdomain is treated differently from a SE perspective, in most cases).