El Dorado vs mythical place

El Dorado and mythical place both are nouns.

Word	Noun	Adjective	Verb	Adverb
El Dorado	Yes	No	No	No
mythical place	Yes	No	No	No

As nouns, mythical place is a hypernym of El Dorado; that is, mythical place is a word with a broader meaning than El Dorado:

El Dorado: an imaginary place of great wealth and opportunity; sought in South America by 16th-century explorers
mythical place: a place that exists only in imagination; a place said to exist in fictional or religious writings

Other hypernyms of El Dorado include fictitious place, imaginary place.

El Dorado (noun)	mythical place (noun)
an imaginary place of great wealth and opportunity; sought in South America by 16th-century explorers	a place that exists only in imagination; a place said to exist in fictional or religious writings