What should be the historical identity of uttar pradesh?

The ethnic identity of any province or nationality depends upon its historical viewpoint. With examples to Indian states : Tamil identity comes from their chola and pandyan empires and of course the sangam period Bihari identity has many forms but mainly comes from the rise of magadh (c\~544BC). But acknowledging the historical identity of such a big state like uttarpradesh seems very difficult . One could argue that its identity comes from the period of lord ram but we have very less evidences to prove his historicity. The Indus valley civilization certainly influenced uttar pradesh but again with a very limited power. The new archaeological findings of sinauli may suggest that there may have been a civilization prior to the vedic age but it still does not have any authoritative evidence to support that. In the classical period some historians argue that the origins of Gupta Empire may have been eastern up, but their capital was still patliputra (for most of the time ) of magadh. The kannuj empires could not hold their power for a long time. And after 1100AD - 1200AD the gangetic plains were fully in control of the turks and the uzbeks . Even in the post mauryan times UP was in many controls of the indo-greeks and the huns. So according to you what was the time where uttar pradesh's historical identity was secure from the invaders OR the concept of a historical uttar pradesh can not be recongnized. As far as I am concerned , i can think nothing other that those 4-5 mahajanpadas which were part of modern day uttar pradesh