> Buddhism is the dominant religion in Bhutan, Myanmar, Cambodia, Mainland China, Hong Kong,[5] Japan,[6] Tibet, Laos, Macau,[7] Mongolia, Singapore,[8] Sri Lanka, Taiwan, Thailand, Kalmykia and Vietnam.[9] Large Buddhist populations live in North Korea, Nepal, India and South Korea. China is the country with the largest population of Buddhists, approximately 244 million or 18.2% of its total population. - https://en.wikipedia.org/wiki/Buddhism_by_country

How many ethnic groups do you reckon that to be?

> Islam is the largest religion in Indonesia, with 86.7% of the Indonesian population identifying themselves as Muslim in a 2018 survey.[1][2] Indonesia is the most populous Muslim-majority country, with approximately 231 million adherents.[3] - https://en.wikipedia.org/wiki/Islam_in_Indonesia

> A majority of the Javanese people identify themselves as Sunni Muslims - https://en.wikipedia.org/wiki/Javanese_people

> Today, most Sundanese are Sunni Muslims. - https://en.wikipedia.org/wiki/Sundanese_people

> The majority of Madurese practice Sunni Islam. - https://en.wikipedia.org/wiki/Madurese_people

How often is Indonesia mentioned in the Koran?

The ethnicity of biblical people is mentioned only peripherally in European Christian practice. Actual representation of the ethnicity of people in the Levant is a trivia question, an amusing aside in Western Christianity; Jesus is blonde.

I'm just saying, don't run too far down that line of thought.