Can I operate a 4-lane MIPI DSI Display from just one lane connected?
I read a little more into some data sheets, especially the driver ICs, exposing most of available displays connector pins. Seems it is generally given by the driver IC how many lanes to use (i.e. RM67191 IC can handle 3 or 4 lanes, which is determined by the wiring of the IC, normally given fixed by the display of choice).

A possible solution to nonetheless use any display to a given setup is by using a driver IC (i.e. SSD2848) which can often handle n-lane input to m-lane output, providing some extra features (frame buffer, resolution scaling, ...) which for some application might be an overshoot of an extra IC, instead of just searching an display with adequate lanes for your applications directly.