I used to think the Mitanni are an earlier branch of Indo-European like the Hittites.
But you are right, the Mitanni ruling elite were Proto-Indo-Aryan. https://indroyc.com/2025/06/01/vedic-influence-in-ancient-middle-east-hurrians-to-mitanni/#:~:text=A%20%E2%80%9CSuperstrate%E2%80%9D%20Elite%2C%20Not,practice%20their%20own%20indigenous%20traditions.
In the treaty between the Hittites and Mitanni (c. 1380 BCE), the Mitanni kings invoke the gods Indra, Mitra, Varuna, and the Nasatyas—the core pantheon of the Vedas.
Thieme, P. (1960). The ‘Aryan’ Gods of the Mitanni Treaties
https://www.researchgate.net/publication/297938476_About_the_Mitanni-Aryan_gods
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Primary Human Language Families
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