There is a Marhaba lounge in both Councourse A and B of Terminal 3. Not sure which is under repair.
See website below. It says you can spend 4 hours there (not sure if anyone is checking the clock though... likely fine for a 6 hour layover once you factor in time to get off the plane and boarding for next flight)
https://www.marhabaservices.com/source/lounge.aspx