Czesc Marek.

1. Search in database if you haven't use that link, if yes, update to current version.
2. Use Google Search Console > Removals > New Request > add that URL to remove it
3. Add redirect in .htaccess file

Sometimes Google index things that we don't want to. You have to talk with Google Team to know why.

The address is not yet indexed by Google

https://www.xml-sitemaps.com/

but it is detected as the only one : " component/sppagebuilder/.."

I'm trying to understand why

can you help me how to do this redirection, I've tried everything

RewriteEngine On RewriteCond %{REQUEST_URI} ^/component/sppagebuilder/$ RewriteCond %{QUERY_STRING} ^Itemid=306$ RewriteRule ^(.*)$ https://ien-24.pl/ [R=301,L]

the administrator wrote me to do as above, it doesn't work

I would try classic method for all "buggy" links

Redirect 301 /OLD-LINK https :// NEW-FULL-LINK

You can also ask on FB Joomla fanpage (PL or others), This is not my speciality.