As owner of the Experience Builder Custom Widgets Group and co-creator of the Custom Draw Widget, I have seen many requests for being able to save drawings created by the Widget. The most logical way to do this would be to take the graphics generated by the Widget, convert them to a client-side FeatureLayer and then save them as a Hosted Feature Layer on the Online/Enterprise Portal. However, there is currently no support for creating a new Portal item from scratch in the JavaScript API. I would like a built-in method for creating a Portal Item from a client-side FeatureLayer.
https://community.esri.com/t5/experience-builder-custom-widgets/re-designed-draw-widget/m-p/1352200