glossaries-extra package FAQ
If you need to include all entries provided in the .bib file(s), regardless of whether they’ve been indexed in the document, then you must use the
selection=all resource option not
\glsaddallunused. These iterative commands can’t work with bib2gls because they iterate over all defined entries but the entries can’t be defined until they’ve been selected. The
selection=all option works better than either of those commands as it doesn’t cause an unwanted location.
Alternative link: https://www.dickimaw-books.com/faq.php?itemlabel=bib2glsselectall