How to get metadata field into search results

[ditoy gmbh]

We are implementing a rating system for resources (mainly images) based on a metadata field (called 'rating') presenting a dropdown of options. We found out, where the dropdown (and other option fields) data is stored in the db (reference to node table entries). Using the config option `$data_joins = [86];` we can join the field into the search query, but something is missing (empty field in result) probably because it is not just a text field with content.

How can I get the option content into the search result in order to display the rating on the thumbnails?

I might be missing an essential resource but this seems not to be discussed anywhere in the dev documentation.

Note: we tried the configurable built-in user_rating mechanism, but we need something we can restrict to a certain user profile.