Generally 5 to 20 minutes in line - it’s possible to get in the queue and never really stop until the boarding area. Usually a few stops and starts in the line, but never for very long - most of the wait simply is the time needed to walk the queue. The line still goes through the preshow room, but it’s not playing - only a “screen saver” that has Hagrid’s dog walking around. The length of the queue can vary as the configuration changes - sometimes the switchbacks (in the external queue by Hagrid’s hut, as well as in the internal queue in the egg room) are open, sometimes you’ll skip them entirely.
The biggest bottleneck usually is around the entry corridor in front of the Hogsmeade station where they check/scan VQ codes before the lockers. Occasionally they will have someone scanning codes directly in front of the ride entrance for riders without bags, but that’s not consistent and they’ll usually send everyone down to the entry point at the train station whether they need a locker or not.