Is there a list of ArcPy functions that can use feature services directly for input? For example, arcpy.da.TableToNumPyArray will happily use a FS REST endpoint URL directly as an input and from there you can do all the awesome NumPy stuff you want.
On the other hand, arcpy.MakeFeatureLayer_management will not accept the URL as an input. It will accept the layer reference in the TOC if the feature layer is added to Pro and you are using the Python window.
The issue isn't solved with the ArcGIS Python API. Yes, there is the arcgis.features module, but despite being able to call up a Portal item as a 'Feature Layer', this cannot then be passed to an ArcPy function. The Python API is great for a lot of things, but obviously doesn't leverage all the power that ArcPy brings to geoprocessing.
So, is there a list of arcpy functions compatible with feature services? Perhaps the Data Access module is the only set of functions that is?