What is the reason I can't discover my created layer in my content?
Late reply. Looking at your second screenshot, it appears to be the source file for your created layer. For example, when I upload a shapefile to AGOL and create a feature layer from it, I end up with 2 files from the single upload. One is the shapefile (source) and the other is a feature layer (publication).
Referencing the picture above, select the item that your layer is published as. In my case, it is the "SplicePoints" link. This should get you to the page you want.