The facetName and facetValue parameters are used by the Recommend API to guide which recommendations the model should retrieve, based on the facet name/value pair. Using these parameters, the model will return recommendations up to the maximum number of items specified by maxRecommendations.
Note: Only a single value can be set for each of these parameters (i.e. one facetName and one facetValue).
In contrast, filters declared within the queryParameters parameter act as post-retrieval filters. This means that they are applied after the model has fetched the initial set of recommendations, further refining your recommendations. This post-filtering process can result in a smaller set of recommendations than when using facetName and facetValue. It is possible to pass multiple filters using queryParameters.
You can read more on the parameters here.