Can confirm this. My local Ranger arrived around 4:30pm and didn’t get the software to finish downloading & installed until 11:30pm. Some of that was a software glitch, but even with me tapping into my router and giving my car priority (so it gets all the bandwidth) it was still a slow assed process. He also shared a couple horror stories about other times he’d done this upgrade where he’d had to drive around to find a decent connection for the download. -.-He stressed the main limiting factor is the wifi speed. Some jobs took him 8 hours as the customer did not have strong home wifi signal to the car.
Current hope is that Rangers will be given Starlink receivers as part of the first closed beta tests so they can get more reliable download speeds.