Where is the most standard Mandarin?

I think it is Xinjiang. I don't know why I read so many answers, and none of them mentioned Xinjiang. Maybe I don't know much about Xinjiang.

First of all, Xinjiang is an immigrant province, similar to Shenzhen, which is found all over the country, so no dialect can occupy an absolute advantage. Especially in Corps cities, Mandarin plays a role in all aspects of life. Of course there are exceptions. Old Xinjiang dialect does exist in Wuchang area (Urumqi and Changji). I have lived in this area since I was a child. I deeply feel that the dialect of my parents is not as authentic as that of my ancestors (probably because of the popularity of Putonghua), but I can speak authentic Xinjiang dialect in my generation (post-90 s) (Xinjiang dialect refers to the local dialect of the Han nationality in Xinjiang, not Uygur! There are very few students, most of whom only know a few words and can't speak coherent and complete dialect sentences. In addition, the absolute Putonghua education in school daily teaching makes Xinjiang dialect less and less in daily life, while Putonghua is more and more energetic.