Please check the demo for your reference:
Also, please check the article:
I have already seen the documentation and there is no information on how to save changes back to the Database. Is there a way I can identify new/changed/deleted records?
Well, we do support to bind the worksheet data with database, see the following links:
But again, since you are binding with custom collection, so I think you need to write your own .NET code to save/update records into database.