IPv6 clients can communicate with IPv6 servers.
IPv4 clients can communicate with IPv4 servers.
In order to mix and match you need some intermediary server that has both IPv4 and IPv6 to translate.
For example my mobile service provider (T-Mobile US) doesn't support IPv4 on their network, however I can still access IPv4 services because they automatically route that traffic through a NAT64 server, which translates the IPv6 from my device into IPv4 heading to the IPv4-only service.
T-Mobile actually takes it a step further than many other IPv6-only service providers. NAT64 alone only solves problems with servers that are IPv4-only, whereas T-Mobile uses 464xlat (which includes NAT64) which also solves problems with apps on the user's device that are IPv4-only.
That dock uses a DisplayLink chip.
A DisplayLink chip is essentially a tiny GPU that handles the final outputting to the display. When the DisplayLink chip is in use the laptop's GPU still does 99% of the work, but the DisplayLink chip handles the final outputting to the display.
This has the major advantage of allowing it to work with a much wider selection of devices (almost anything with a USB port and a DisplsyLink driver available), however the additional complexity and drivers can lead to some finicky behavior and artifacting. Overall I suggest avoiding DisplayLink docks unless you actually need the benefits.
For the Framework Laptop most Thunderbolt 3/4 and USB4 docks should work, but not all.
USB4 supports two different methods for a dock to run multiple monitors. The computer can send multiple separate display signals to the dock or the computer can send a single (higher bandwidth) display signal that the dock can then split into multiple display signals.
From the end user's perspective those are identical as long as they work, however AMD USB4 controllers (like the ones in the FW16) only work with the latter method (single display signal that is split) whereas MacOS works better with the first method.
Most USB4/Thunderbolt 3/4 docks use the method that works with AMD, however some docks that are marketd towards Mac users will not work. The most common docks that won't work are Caldigit docks.
If you want a docking station that works with either the Framework or a MacBook then that may be a good reason to use a DisplayLink dock.