This is some code that I've used to nuke clear out Survey 123 items and services from an org that I use during development on the ArcGIS Hub product. It is ruthless and cruel. It is not graceful in any way. If the user you run this as owns ANY Surveys or Survey related feature services, it WILL destroy them. This code is soooo terrible - it just brute forces things into oblivion. What it does not remove, it breaks horribly, and then you run it again, and it will remove it.
This is only on github as an example of a one-off script that uses the ArcGIS Rest Js library to interact with ArcGIS Online.
Running this code will likely destroy things for you. You do NOT want to use this. Seriously. Turn back now. Run.