The Iran-Persia confusion goes back to antiquity and ancient Greece, and is somewhat similar to modern English’s confusion of Holland and Netherlands. Holland is the largest province in the Netherlands. Likewise, Fars was the largest province in ancient Iran, and the Greek word for Iran gave rise to modern English “Persia”, but Iranians always used their country’s equivilant of “Iran” to refer to the country as a whole.
Farsi (Persian language) is an Indo-European language like Hindi, English, and the Celtic languages. The IR- stem in Iran comes from the same Indo-European stem as Sanskrit “AR” in Aryan and “IR” in Ireland.
You entertain me for decades with movies of the Battle of Thermopylae between 300 waxed Chip-n-Dale dancers and the massive army of circus freaks with their body piercings and jeweler.
Now I hear and watch of talk that the Circus freaks went snowflake and want to go back to be called Persians and want to be rescued from persons who say they are them, but now you tell me they are just Netherland people.