Sovereignty means the right to act as final judge in all disputes, including disputes involving the sovereign itself/himself. The Indian tribes are not sovereign or anything like it, despite what treaties may say.
I would make the tee pee tippers sovereign on their reservation but block the highways in and out and require a passport and toll to exit the reservation.
When the states separated from England was it not sovereignty they declared? My point is Sovereignty is not something granted by other states but rather declared by a state(Nation) itself. Add to this knowledge the fact that the treaty’s, most of them, allowed and maintained the different tribes were recognized as Nation States.
By the way Sovereignty means much more than what you think it means.
Sovereignty
The supreme, absolute, and uncontrollable power by which an independent state is governed and from which all specific political powers are derived; the intentional independence of a state, combined with the right and power of regulating its internal affairs without foreign interference.
Sovereignty is the power of a state to do everything necessary to govern itself, such as making, executing, and applying laws; imposing and collecting taxes; making war and peace; and forming treaties or engaging in commerce with foreign nations.
God Bless