Why does the search not return the desired results?

Basically: The Shopware search unfortunately deteriorates the longer it is operated. This can be read in the ticket: https://issues.shopware.com/issues/NEXT-20223 This can be remedied if the two database tables product_keyword_dictionary and product_search_keyword are completely emptied and the search index is then completely rebuilt (under Settings > Shop > Search > Real-time search > Rebuild search index). In new plugin versions of Search Pro, there will be an option for this directly in the admin. However, this does not apply when using Elasticsearch, but only with the Shopware standard database search.