"In the article it says the Kingdom of Hungary existed continously for about 986 years."
No: the article says the Kingdom of Hungary existed for 946 years with minor interruptions. I had removed "minor" (before your comment here), otherwise that is correct.
I added a reference for the Trianon part (The New York Times). Suddenly millions of Hungarians found themselves outside of Hungary against their own will, how could you present this as non-controversial?
I think this article is pretty fair and neutral compared to other similar articles about countries, for example the article Romania.