any 5-6 hour flights for the new a330 neo?
I think most people will point you here: The Airbus A330-900neo Route Database
I do have one though, JFK-AMS with the Delta A330-900 is just outside your range. About 6:30-7 hours.
KJFK-KSEA is one
TAP has a lot of 5-6hour flights on the neo. Ones that i recomend:
OPO-EWR and more (you can check out on their website)