I'm not aware of any laptop docks with built in graphics. Normally the video outputs just expose whatever display output capabilities the laptop has through the thunderbolt protocol (displayport over usb c)

There are solutions for Thunderbolt that allow connecting external graphics cards (eGPU) like this one from Razer, but the typical docks just forward the signal.

Edit: Updated link

There's no real graphics hardware in MOST docs, but some USB docks labeled display link actually have a little display adapter in the dock that is written into by your gfx card.

Also thunderbolt and to a lesser degree displayport send (or can send and often dont) partial screen updates making the endpoint do some graphics card like work.

Otherwise there are usually chips that convert formats, displayport to hdmi, etc, and logic to handle resolution negotiation which a lot of docks get wrong and leave you with 1080p when you should be seeing 4k.

Anyway yes you're mostly right "But ahkshually!!!"

No the docks don’t have any video processing capability, they either convert the usb-c to video, or they have a driver like DisplayLink. In the case of Dell, the usb-c docks are limited to one 2k or greater monitor at a time, so you can have a 2k and 1080p, but not 2 x 2k or a 2k and a 4K.. the Thunderbolt version of the same dock has no such limitation

Some good answers here. Thanks.