A lot of phones can be connected to an external display via USB-C. Better supported than MHL (how many incompatible standards was MHL? 4?).
Samsung has "Dex", their android desktop interface.
Linux phones can generally offer a full DE, either the pinephone or Librem, or compatible phones that have a video out where you can install something likke postmarketos.
Most phones also support miracast, and you can plug in a mouse/keyboard. I think the Charging in + keyboard + mouse + video out is clearer with USB-C.
Sent from my Galaxy S4 ;)