From a post from one of the Framework team, they revealed that it will be two, one handling left side and one handling right. Each one gets two USB-C ports.
@djph All 4 expansion cards are routed to the same USB3 controller.
USB3 signals all ports → USB controller 1
USB2 signals all ports → USB controller 2
so last I heard, and staff can correct me if I’m wrong, but all 4 ports are thunderbolt 4 compatible, they just can’t call it thunderbolt 4 yet because of the certification process. I was told that there are 2 thunderbolt controllers one for the left side and one for the right side.