Currently, Detect Objects using the Deep Learning tool does not support the inferencing of models trained using TensorFlow backend.
Please refer to Object Detection Workflow with | ArcGIS for Developers, Detecting Swimming Pools using Satellite Imagery and Deep Learning | ArcGIS for Developers to understand how You could do Object detection using arcgis. learn module.
Moreover, if you want to train a model with a TensorFlow backend, you can do that and save a tf-lite model then deploy it on mobile using the Survey123 app. To understand that, follow Training Mobile-Ready models using TensorFlow Lite | ArcGIS for Developers.