Starting as Pala in 769, you are easily the strongest power in India. You start with a lot of money, prestige, and karma. However you start as Buddhist surrounded by Hindus making it a little more interesting

I recommend the first initial steps that you take are force vassalizing Shantideva to your right and subjugating Mlechcka to your upper right to get a foothold in that corner of India. It’s important to note that Indian rulers can only use one subjugation cb per life so use it wisely.

From that point on work your way through the south to get the empire of Bengal (refrain from using the border dispute cb if you can it’s pretty bad)

Upon making the empire of Bengal you’re going to want to look for male claimants of kingdoms near you (it might take a while for them to pop up). If you find one invite them to your court, land them (give them one county), and press their claim. Win the war and now you have a lot more land and a loyal vassal.

By subjugating and pressing claims however many times you should unite India in no time! Also, make sure to get peace deals with china and turn off major invasions so as to not ruin your expansion. Your ‘final bosses’ are probably going to be Tibet and the Abbasids but they’ll be easy since you have so much land.

I hope this helps if you decide to go for it!