I want to use 4K 60hz monitor in RBS 2019

RBS 2019 has one usb3.1 C type port and one Thunderbolt 3 port. I connected it to a 4k 60hz monitor with a C to hdmi 2.0 cable. However, the left USB 3.1 port was 4k 30hz, and the right port had no response at all. My guess is as follows: The USB 3.1 port on the left of RBS 2019 is HDMI1.4v, and the Thunderbolt 3 port on the right does not operate unless power is supplied together. Thunderbolt 3 port does not seem to work unless a hub capable of supplying PD power is used. Is that right?