Can you please explain on what you meant by "HUB type protocols"
I just mean that its a protocol that allows for many devices to connect. Including devices that create more ports for more devices. The computer talks directly to all devices on the bus. The computer doesn't need to mix multiple different signals together, that is done in hardware. The computer isn't really talking to its USB-C port, it's talking to all the devices on the bus.
1. For sharing the bandwidth of the connection, should all the devices need to be connected/configured (not sure of the exact term) in daisy-chain format.
The data rate is limited by the USB protocol. Engineers design their USB devices to use less than the total available datarate. The engineers also consider what to do if the USB bus is busy and they can't get the data rate they want. The design the USB device to handle this situation. A USB to HDMI adaptor for example would probably lower the frame rate or just skip frames. Other devices may refuse to work or show errors if they can't get the data rate they need and can't function because of it. Like in real time monitoring.
Windows will also warn you if you have too many USB devices on one USB bus.
2. Can you explain the calculation of 60fps 1080p into 3.6Gpbs?
I googled it and went with the first result, it looks like the actual value is 3.73Gbps.
1920×1080=2,073,600 pixels per frame
2,073,600 pixels × 30 bits color info per pixel = 62,208,000 bits per frame
62,208,000 bits per frame × 60 frames per second= 3,732,480,000 bits per second