Moving the goal post fallacy. You established that number of languages and ethnic groups present was the criteria for measuring diversity. Once your criteria was challenged, you then introduced a new methodology based on a researcher using fractionalization, a methodology that happens to achieve your conclusion.

The US is a very diverse country given its constant flow of immigrants and lack of lengthy history or genealogy. Can you claim other places are more diverse that have a bunch of tribes and ethnicities that belong to greater ethnic and linguistic families? Sure I guess. Certainly can’t try that claim in most countries though. Most are low immigration, low minority counties. European counties are basically ethnostates that don’t come out and say it. But the numbers and immigration policies don’t lie.