At my spiritwiki.org i have 2100 pages.
I get pairs : <url>
<loc>https://spiritwiki.org/w/Datei:Chakrasamvara_Vajravarahi.jpg</loc>
<priority>1.0</priority>
<lastmod>2022-03-26T15:32:45Z</lastmod>
<changefreq>weekly</changefreq>
</url>
<url>
<loc>https://spiritwiki.org/w/Chakrasamvara</loc>
<priority>1.0</priority>
<lastmod>2023-02-12T22:11:57Z</lastmod>
<changefreq>weekly</changefreq>
</url>
and not all sites.
What do you mean by "all sites"? Maybe "all pages"? What namespaces are used in your wiki instance?
if You look at my wiki : The namespace is /w/ - all other is standard (i have now deactivated the plugin and use another sitemap)
P.S. In the wiki is a site 'All Pages'. Using the source-code of the wiki instead the code of this plugin would avoid such jpg-errors - and also would make the variable
$wgAutoSitemap["exclude_namespaces"] = [ superfluous.