I would like to publish FeatureSets (point geometries) with varying fields to new map services. Basically, I am uploading an Excel file, letting the user do some simple field manipulation and then send the results off to a GP task to be viewable via a map service. The reason I am not doing this all client-side using FeatureLayers is because I need to be able to let the users filter by applying definition expressions.
This is for a solution which is not part of ArcGIS online. ArcGIS online has a function which does pretty much exactly what I'm looking for, except mine does not need to be a feature layer per se- Just a map service. Publish hosted feature layers—ArcGIS Online Help | ArcGIS
I currently have a GP task which publishes results to a map service, but it needs to be pre-generated from a FeatureClass and it does not support changing schema.
Here is a few screenshots of my current progress: https://imgur.com/a/nfISW
Happy to provide more info.