Those Dell ones that come with the XPS caused us endless problems at work. Higher res screens would just not work properly. The only one that consistently just worked was the apple HDMI/USB-A/USB-C charging dongle.
Sounds to me that you for some reason got the older USB-C 3.1 / Gen 1 docks those are limited to 5gbps which means no 4K@60 the Gen 2 USB-C / TB3 docks work quite flawlessly as long as you ofc plug them into a Gen 2 or TB port…
With USB->DP adapter yes. With a hub offering USB3 ports, mostly no. Once both lanes are in DP-alternate mode (needed for 4k@60), there's no bandwidth for USB3, only the separate wire for USB2. So here it depends how it is internally connected, and whether it can switch USB3 ports to USB2 or not. Many hubs can't do this.
I've been running an Intel MacBook Pro (last intel version I think) on it the last few months with 2 external HP displays, keyboard, mouse, and it is a solid performer.
Yes, those displaylink docks are fine for office productivity work, but not that suitable for gaming or media consumption because of the cpu load. On the other hand, I plugged my m1 air into one at work and the cpu load was reasonable even while videoconferencing, so I suppose eventually the overhead of displaylink gets small enough not to be a problem.
As another commenter stated, bleh to DisplayLink.
Also, what monster designed it so 1! of the 4 USB-A ports is upside down? This is why we cannot have nice things.
Do not waste your money on high end consumer stuff, the enterprise stuff is better and the market is flooded with disposed units…