On Duolingo and Google Translate the pronunciation of ę is like an open ɛ sound.
Needs more research... Native speakers, please help with your knowledge intuition :)
Word-final -ę can be pronounced as either /ɛ/ or /ɛɰ̃/, the former is the usual pronunciation, the latter is used to disambiguate in the situations when the difference would matter.
The forvo recordings sound hypercorrect and even a bit pretentious.
Mid-word ę is pronounced as /ɛ/, /ɛn/, /ɛŋ/, /ɛɲ/, /ɛɳ/, /ɛm/, or /ɛɰ̃/, depending on the following consonant.
ę is never pronounced /ɛu/.
Well, ɛu is the closest I could come up with to describe this little swing made at the end :) I just started two days ago, so I don't know many things, sorry.
I see, I'd prefer ɛ, it's a lazier and simpler sound than ɛɰ̃ :)
Thanks a lot!