Given that these ship with 180W AC adapters, and further given that the i9 CPU draws as much as 45W just by itself, while the system may charge with a smaller capacity adapter, it won't run at anywhere near full speed using one.  
Would anyone know, if in the I9-11950H configuration with two RAM cards, 1 SSD, and only integrated graphics, if the Precision 7560 workstation could also be charged and operated solely off of one USB-C port rather than the 180W barrel connector? I would imagine that without the discrete GPU, the power load would be less than the 100W limit of a standard (non-Dell) USB-C adapter, but I'm not sure if the computer would physically let me do this or whether my hypothesis is correct. (After all, the BIOS might disable the feature with only one port or reduce its performance despite --possibly-- being in the operational window.) I'm particularly interested in whether this works with a "standard" USB-PD charger rather than the proprietary 130W one.
Details on USB-C power for the Dell Precision 7560 Workstation