What if the Treaty of Yandabo had never happened? How would Assam and the rest of the Northeast region be today?

I am assuming the Ahom kings would’ve probably not integrated into Indian rule post-independence, and consequently, the rest of Northeast India would also not have been under Indian rule.” Assuming Assam remained independent, would it have annexed the other hilly states of northeast India like Arunachal, Nagaland, Mizoram etc? Maybe Assam and Manipur would’ve been competing against each for territory and influence in the region? How would Assam’s economy be today?