Just did this type of transfer. My flight from JFK landed late so lots of people missed their flights.

We parked at the domestic gates so had to use the bus to go to the int’l arrival lounge. There’s a seperate passport/customs for domestic transfers and there was virtually no line at 6pm which is a busy time. Then you go through a separate security for domestic transfer passengers which also did not have any lines.

I’d say to leave at least 1.5 hrs to be on the safe side