Thanks for your inquiry.
I’m afraid there is no built-in way to compare or delete styles from the document at the moment. I have linked your requests to the appropriate issues. We will inform you as soon as there are any developments.
In the mean time you may be able to work around a solution by comparing the styles through the use of a byte array as demonstrated in the code here
. The technique seems fairly reliable. Secondly, you cannot remove a style from a document, however you could change any content using a duplicate style to using just one style and then inserting all of the document content into a new document. This should result in only the one style appearing in the document.
This does sound like a bit of work though, I would highly suggest waiting for the original features to be implemented in the API instead.