Before I start digging deep, I would hope that someone used these features

to create a function which creates a ZIP archive from a a list of root
elements and collecting all contained files automatically. My XSLT create a
lot of files and folders using xsl:result-document and at the end I would like
to zip this up.

Perhaps XProc is an option:
https://spec.xproc.org/lastcall-2020-08/head/steps/#c.archive