Filter query not effective

The current request on the endpoint when you type in your filter is this:

where=Beheerder+LIKE+'Z%25%25%25'&
outFields=*&
spatialRel=esriSpatialRelIntersects&
resultRecordCount=500&
featureEncoding=esriDefault&
f=pbf

This will fill the list with all values you can chose from.

But this would be way more effective:

where=Beheerder+ILIKE+'z%25%25%25'&
outFields=Beheerder&
returnGeometry=false&
returnDistinctValues=true&
resultRecordCount=500&
f=pbf

For the filter list we don't need the geometry or all other fields. We even don't need every record with a value that matches, only the unique ones. And I think it should be ILIKE not LIKE because users are not used to have case sensitive fields on default.

I also made a ticket at Esri because our HostedMapImage layer does not listen to the Distinct parameter, where SDE services do listen to it.

Also the field does not allow to start typing with %. But removing the z from z%%% will query with ‘%%%’. So please fix it so I don't need this workaround.

Possibly related:
https://support.vertigis.com/hc/en-us/community/posts/12131964735762-Autocompletion-for-Value-field-in-Query-and-Filter-tools