Completely optional, but why not have some fun. By this point there should be weak Indian nations in the Bengal area willing to sell you a province for a few thousand ducats. Use the Charter Company diplomatic option, invest in the District and Military Administration, and tick the achievement. Nothing critical, just a detour if the opportunity is there.

Completely optional, but if any of the colonial powers present in India — Portugal, Castile, England — are willing to sell you a province in the Bengal area, it's a fun detour. Grab it, invest in the District and Military Administration, and tick the achievement. Nothing critical, just a bonus if the opportunity is there.