Original spilt of the Raj was more complex even than you indicate
We already know that British India resulted in the three states of Pakistan, India, and Bangladesh. What other ways could India have been split? Could Sikhs have clamped for self rule as the Muslims did? Could India have divided up based on its internal cultures, maybe north/south?
The Hindus (lead by Nehru) insisted on taking control of as much of the former Raj as possible, and unfortunately were granted much territory with separate racial and religious traditions such as the Sikh Punjab. Since independence there has been resistance to the rule from Delhi in these areas, mostly being repressed by military force.
However in the 1940s the Muslims lead by Jinnah were able to insist on a separate state based on religion (not race). This is what is generally referred to as the Partion of India. It created the original state of Pakistan, which included the racially and culturally separate areas of East and West Pakistan.
That division alone resulted in millions of deaths in the immediate aftermath of partition as families living on the wrong side of the boundaries fled ethnic/religious cleansing in all parts of the subcontinent.
The resulting enmity has repeatedly sparked wars between India and Pakistan that have killed thousands more and created two nuclear armed enemies.
Of course, the religious based union of Pakistan did not last. West Pakistan dominated the political landscape and the East Pakistanis were racially and culturally very different. With encouragement and massive military intervention from India, East Pakistan established itself as Bangladesh.
Similarly though Ceylon was originally kept separate on geographical basis, the ethnic mix of native Sinhalese and Tamils from the mainland of India resulted in Civil War, with India first offering clandestine support to the Tamil Rebels, then openly supplying them by air finally sending 100,00 troops to enforce a peace agreement. When the Tamils refused to disarm, the Indians withdrew and the fight continued for 20 years off and on.
This does not include Bhutan, Nepal and Burma created from the Raj on racial and cultural grounds, each having their own problems.
Or the mess in Kashmir, where a Hindu royal family in charge at the time of Partition took a mainly Muslim population into India, resulting in 70 years of conflict.