> And the actual name for Greece is Hellas.

That's many centuries out of date. You want Ellas. The aspiration was lost long ago.

(We might also note that the Greek wikipedia page is titled Ellaða, but the first thing it does is list Ellas as an alternate name.)

They didn't always call themselves Hellenes, at one point the more common names were Achaeans (hence Egyptian "Ekwesh"), Danaans and Argives. The word "Hellenes" is only found once in Homer. Or often people called them by their specific tribe, such as Ionians or Dorians. Some languages use older names because that's what they are used to. It seems that country borders, politics, self-identity etc. change faster than language.