Hi @diepic,
I expect that the internal name of your column does not have square brackets. You can lookup the name of the column in Dataverse. Below is an example within my environment.

In case of a Lookup it probably is easier to filter on the GUID of the lookup record in the _publisherprefix_InternalColumnName_value property.
In my example that would be like below:
_crca4_categoriadocumento_value eq b918119d-0872-eb11-a812-00224840eb4b
