I'm finding out within our AGOL there is a lot of One Trick Pony Feature Layer/Table. Is there a way of moving Feature/Table under one Feature Layer similar way ERSI template are created (Manhole Inspections)?
If you have ArcGIS Pro/ ArcMap, create a relationship class between the layer and the table (Add both the layer and the table to ArcGIS Pro). Then follow Share a web feature layer to publish your data to ArcGIS Online.
See @KoryKramer's steps in Solved: Publish hosted feature service with related tables - Won't work with ArcGIS Pro 2.0