I cannot for the life of me figure out how to delete rows in the feature table. The layer is set to allow editing – it seems like there should be some obvious button somewhere that I am unable to find either here (see attachment) or in either map view. What am I missing?
In the AGOL interface, you can only delete specific features like that by clicking on the feature in map view and clicking delete in the pop-up (while in editing mode). If you want to delete a bunch of features at once or just want to stick with the more familiar attribute table interface, you can manage hosted feature layers by pulling them in to ArcGIS Pro. In that interface, you can delete by selecting a feature (row) in the attribute table.
Hope that helps!