I gotta tell you, being a Spanish speaker from Latin America, almost no one will ever use the sound "sh" in South America to say "saludos" never! Also, if they said " setaos" they are from Spain, no doubt! That conjugation exists only in Europe. Some people in America will say"siéntate" if they are very familiar with you, it's a conjugation for the pronoun "tú" and they might also use "siéntese" for the pronoun "usted" almost unused in Spain.
In South America you can also hear "sentate" which is derivative of "vos" a wierd combination of "tu" and "usted"
The explanation for that comes from the origin of the colonies in certain parts of America.... it's a long story
Hope that helps 😁
Saludos = from Spain, no doubt. Try searching for accent from Madrid or Barcelona. I'm pretty positive you'll find a match