We could use a production wiki's action=query&prop=growthimagesuggestiondata API as the upstream image recommendation source on non-production wikis. That has limitations compared to the current MvpImageRecommendationApiHandler (it might not be available in a given language, it's slower), but it provides up-to-date recommendations, plus the MVP API might be undeployed at some point.
This is moot if T306349: Public-facing API for querying image suggestion recommendations and submitting user feedback gets done (it provides the same data without the limitations and in format the existing handler expects) but currently the schedule for that is unclear.