Elasticsearch Mapping Configuration for Models

Hello, I have a question regarding the configuration mapping for elastic search in Neos with https://github.com/Flowpack/Flowpack.ElasticSearch.ContentRepositoryAdaptor

I have the following node:

   'TYPO3.Neos:Content': true
     type: 'Vendor\Site\Domain\Model\User'
         type: "string"
         include_in_all: false
         index: 'not_analyzed'

As you can see, I’m saving the user object to the node and already tried to apply the default mapping.
Now I want to get all nodes of this type which belong to my logged in user. I’m fetching the logged in user with an EelHelper in Fusion. I know that the helper returns the correct user because I’m using it already without problems.

My query looks like this:

user = ${Vendor.Site.getParty()}
${Search.query(node).nodeType("Vendor.Site:NewsLike").exactMatch('user', this.user).execute().count()}

Nothing is found.

I know I can solve this by using this plugin https://packagist.org/packages/flowpack/listable and using a flow query, but I’m already using elastic search and want to use it for this as well.
Working FlowQuery example with listable:
```${q(site).find(’[instanceof Vendor.Site:NewsLike]’).filterByReference(‘user’, this.user).count()}`

I think the problem is within the configuration of the elasticSearchMapping in the yaml file, but I can’t figure out how to set it correctly to respect / index the User model. Is this possibly at all? Thank you!