Help! Tatar versus Tartar

There are some linguistic assumptions regarding the proper name Tatar.

Some Anatolian Turkish academician and linguistis claim that the self designation name Tatar can not be necessarily of Monolian origin., although the name showing Mongolic characteristics.

I think I am fish minded. I always forget the names of books or articles that I can provide.  So I do not remember again in where I read it. But Some Turkish scientists and experts on the topic says that the Tatar name was consisted of two parts which later amagamated and formed a name.  Acording to this , Tatar is a combination of Tat and Er. The first one meant Foreign , Stranger, Non-native . This tat was used to other peoples that are not of Turkic stock , later it was used to specifically for Iranian peoples.

Er meant man, human

So Tat er meant Foreign man, Foreigner.

Tat+er later turned into Tatar.

If this assumption is true, it also confirms that Turkic speaking Tatars also included some non-Turkic elements and that is why they were called foreigners.

I do not know if this is true. You know some Turkish scientists are really in love with pseudo science.