The first step to finding out is normally to create the desired object manually through the end user interface and analyse the resulting database representation and relationships using RevitLookup and other tools:
https://thebuildingcoder.typepad.com/blog/2017/01/virtues-of-reproduction-research-mep-settings-onto...
Another first step might be to search the Internet, e.g., for something like "revit api create angular dimension":
https://duckduckgo.com/?q=revit+api+create+angular+dimension
That turns up a useful result. Lo and behold, it is right here in this forum:
https://forums.autodesk.com/t5/revit-api-forum/creating-angular-radial-dimensions-using-revit-api/td...
Oh dear, the news does not look good, at least not back in 2019. Apparently, this is not possible programmatically, or we don't know how, and there is an open wish list entry for it:
https://forums.autodesk.com/t5/revit-api-forum/creating-angular-radial-dimensions-using-revit-api/td...
It has 34 votes so far and needs more, so please vote for it as well.
And, to complete the list of options before raising a question: search the Internet, search this forum, search the Revit Idea Station, ...
Sorry I cannot provide an immediate solution for you.