No, the Aryan tribes are reliable, they are mentioned in a huge number of sources, including in the Vedas themselves. And even in the Kama Sutra this people mentioned.
The country of Aryavrata really existed, no one doubts it. This means the Aryan country.
The fact that the true Germans are not Aryans, I do not argue, they are the heirs of the cultures of corded and linear-tape ceramics. The Aryans in Europe are the Celts of the Hallstadt and La Tene cuiturs, not the Germans. They inherited the Aryan culture from Romania, Poland and Austro-Hungary, most of the inhabitants of Germany are not Germans.