Image search is one of the pain points when you want to deploy your own cloud, and what I'd miss compared to Google Photo or that image search in Dropbox.
Is there something like that in Nextcloud for instance? I am aware of a basic face recognition app (https://github.com/matiasdelellis/facerecognition)
PhotoPrism (https://github.com/photoprism/photoprism) includes a TensorFlow model to tag pictures and search them.