See above."Let's see what you're going to say after you've been living in Germany for 3 years."
The present perfect is used after "until", "till" or "after". Would it be possible to
youuse the present perfect progressive instead of the present perfect as in the sentence above?
The present perfect progressive is fine in the second half of the sentence but I would have used the simple present at the beginning:
Let's see what you say after you've been living in Germany for 3 years.
Let's see what you say once you've been living in Germany for 3 years.
How about using it after
"You're not entitiled to have any financial benefits
untilluntil you have been working here for half a year."
That's fine, but note the spelling of "until".
You don't really need "have" in the first part of the sentence. "You're not entitled to any financial benefits..."
If you really want to put a verb there, then I would suggest "You're not entitled to receive any financial benefits..."