Instead, those docks use a technology called DisplayLink which has nothing to do with DSC. DisplayLink means that external monitors are basically "software" displays that are tremendously slower and often very limited in resolutions and frame rates. Having any DisplayLink display connected also breaks HDCP and can cause other problems.
Sorry- I'm horrible at reading Apple Specs and inferring the capabilities
https://www.apple.com/macbook-pro-13/specs/
People have gotten round it by connecting additional screens using display link adapters.
Running external display at 4k@60Hz is possible but not straight forward, it requires patch core graphic framework, or using 3rd party boot loader. Newer models do not have this limitation afaik.
M1 != M1 Pro/Max/Ultra.
If you have an M1 Pro or M1 Max or M1 Ultra, that is not "[your] m1".
Each chip has significantly different capabilities in a number of aspects. As far as display support goes,
M1 = 1 external display[0]
M1 Pro = 2 external displays
M1 Max = 4 external displays (3 USB-C + 1 HDMI)[1]
[0]: the exception is the M1 Mac Mini, which doesn't have an internal display, so it can use two external displays.
[1]: once again, the desktop version without a built-in monitor can support one additional monitor, so the Mac Studio with M1 Max can support 5 displays.
