How about headset, flash drive, extra monitors, Ethernet cable, charging cable, phone charging/data transfer, controller, and even a better webcam and microphone.

You are looking for solutions on a problem that shouldn't even exist in such an expensive device.

Even a dongle is just a workaround.

I can’t think of a good reason to have 3 devices

Sorry to inform you, but your imagination is rather deficient.

I never needed more because I just had a dock. My monitor, keyboard, mouse, and Ethernet cable stayed in the same place, so I'd just bring my laptop home and plug in a thunderbolt dock, and I'd have every peripheral I needed. And I'm someone who tries to use wired stuff over wireless whenever convenient.