I’ve ran into this situation multiple times at my current and previous jobs. I really want to avoid Windows and use something better, but I can’t live without two external monitors.
On Windows, it “just works”. I don’t have to do anything.
On Linux (I tried Linux Mint today) it doesn’t work. First, it only connected one of the monitors, the other one did not register. Then I switched to a different cable from the computer to the docking station and it connected both screens - however, they were locked to 30fps. I could not make them work at 60fps (and this is a major dealbreaker, I cannot live with 30fps).
This isn’t really a tech support question, I’m more trying to understand what fundamentally causes this situation. Why is Linux still struggling with pretty basic functionality that Windows does with zero setup? Is it the vendor of the laptop and docking station that aren’t properly supporting Linux? Or is it some other problem?
If the cable made a difference, then that may still be the limiting factor. It’s not totally unheard of for Windows drivers to be a little more fault tolerant or better tuned for suboptimal cable connections. If you aren’t already doing that, try using a certified cable that supports the bandwidth and features you require for your setup. Besides that I guess you could only try the newest kernel version you can reasonably install.
The cable only made a difference on Linux, not that it worked completely even with the other cable. On Windows, it worked with either cable.
I know, I did read your entire post. As I said, it’s not unheard of for Windows drivers to be more fault tolerant in suboptimal conditions. For example: Windows GPU drivers in the early days of HDMI 2.1 needed a lot of tuning for tiny oltage adjustments to ensure signal integrity if your cable wasn’t exactly up to spec, basically compensating for a “bad” cable, whereas the Linux drivers at the time didn’t really try to do that. This doesn’t have to be the case for you, but it should be relatively easy to test.