You don't need a dock, proprietary or not for DeX on the tab at least, it's just a button there, and I've been able to just use a regular old random dock for external display, external keyboard etc.

Haven't tried with phone though.

But you need a computer to receive Miracast for you. Motorola just has a DP video output to a dumb screen.

Samsung's works with DP over USB-C video output too. A computer to receive is just an additional option.

No? I have an older s7+ and it has a standard usb c port and you can just connect any screen. Nothing proprietary or complicated.

Huawei too! Just plug your phone into your TV. But behind the scenes it’s built on AOSP code (assuming DeX and Motorola are the same)

No dock required. With Samsung DeX you just need a cheap USB-C to HDMI cable. Plug the phone into the monitor and you can switch to desktop mode.

It only works on Samsung models that have USB-C video though. My mid-range Samsung phone doesn't have either feature.

You can do this on completely stock Android, Android already supports multi-window completely natively if you enable it in the debugging options and use a launcher such as Sentio Desktop.

Though I used to use this on phones with a dedicated micro-HDMI port so I'm not sure if just any phone can be hooked up to an external display (maybe most of the ones with USB-C?) but it's definitely not OEM-specific.