Macs do not support DisplayPort MST daisy-chaining or its equivalent. So, in general,
- They do not support hanging more than one monitor off a plain USB-C dock.
- They do not support hanging more than two monitors off a Thunderbolt dock.
USB-A is not designed to support video, period.
If you have a Dell Thunderbolt dock that can drive three or more monitors on a PC, you may find that there are only certain combinations of two outputs that will work properly with a Mac. If you use the wrong combination of ports, you will, in effect, be driving two monitors off a single signal from the Mac, and will be unable to get your monitors to work in extended desktop mode.
Dell Support – Dell Thunderbolt Docks and Apple USB-C Hosts
Extend or mirror your Mac desktop across multiple displays - Apple Support