SceneLayer with associated FeatureLayer (SLwFL) from Multipatch FeatureClass on FileGeodatabase is the only way to go (or at least the most flexible) for building interactive apps because they offer more functionality than simple standalone SceneLayers.
Current state of things (ArcGIS Pro 2.9):
Automating the Creation and Overwrite of SLwFL from filegeodatabase multipatch Feature Class: workflow not documented, the most resembling solution is what i posted in here and it does not work well because of layer settings https://community.esri.com/t5/python-questions/can-arcpy-publish-update-web-scene-layer-with/m-p/448...
For Overwrite/Edit/Upsert/Update SLwFL already available in AGOL/Enterprise, it simply is not documented and currently the idea is to "republish" although it would create a whole different ItemId, it should be like this for Overwriting FeatureLayers https://community.esri.com/t5/arcgis-online-documents/overwrite-arcgis-online-feature-service-using/...
So if you have a large scale 3D model to deploy, and which is dynamically changing? Current solution is either: do it manually with the ArcGIS Pro GUI which is not viable for multiple models or try your luck using the script i posted in the first link. Regarding overwrites or updates, automation simply is not possible (have to rebuild whole feature class again).
So really appreciate your feedback because with this functionality it will be a breeze to do the full workflow: build your Multipatch Feature Class in GIS (ArcGIS Pro) -> Share (AGOL) -> Client Side Powerful Dynamic Dashboards (ArcGIS JS API) all automation.
Some ways to make this multi team upgrade could be: i) make an arcpy hook which can mimick when user right clicks on content pane multipatch ArcGIS Pro scene layer > Sharing > As web layer > share as SLwFL ii) for the overwrite would be for example interesting to revamp the ArcGIS Python API feature_layer.append() to be able to work with filegdb and output SLwFL together with feature_layer.delete() and feature_layer.edit() for example.
Have developed a DIY map application where users have their own scenes, and i have to manually publish each user scene for his/her own application because this feature is not implemented so many thanks if you can take a look at this. Considering that this particular workflow (of Scene automation) is fronted by ESRI capabilities, being next to none in terms of such capabilities. With this solution would make the communication between your products even more in front of competition.
In my opinion is still quite basic and only touching the surface of what is necessary to improve in terms of scenes workflows reason of which making this idea.
Cheers.
