Supplement to the question
(It's a shame you can not really join in here without karma. Unfortunately, I still know too little of odoo to answer questions. I would like to actually extends the question with a comment. I'll do it here...)
I also look for a way to adjust the sitemap.xml.
first I'm going to Settings> Technical> user-interface> views. With the filter "sitemap" I get the templates. I assume that there changes can be made.
Problem is: I have tried many things but no matter what I do, it does not change the output. Must there somewhere a cache are deleted?
I suspect something like that could help to output not all pages:
<t t-if="page.get('lastmod', False)">
<url t-foreach="locs" t-as="page">
<loc><t t-esc="url_root"/><t t-esc="page['loc']"/></loc>
<t t-if="page.get('priority', False)">
<t t-if="page.get('changefreq', False)">
so that only pages are output that have already been edited. Surely it would be even better way. The ideal would be a setting in the metadata of the page self.
After all, such sites should never be displayed:
/crm/contactus (second Contact Page????)
/shop/product/inactive-7 (inactive product end in 403)
/partners/country/amerikanisch-samoa-12 (not used Countrys)