I was thinking about that. I see that there are “adapters” that claim to be 30 pin to 40 pin eDP. And I see that the difference between the common 30 pin vs 40 pin is just dropping 2 lanes and a couple less of the duplicated VCC and GND pins. So pinout wise, there is some potential for those adapters. Wouldn’t just trust them though, need to confirm with a multimeter.
Beyond the pinout, I don’t know enough about how eDP is usually implemented to know if it’s likely to seamlessly accept only 2 lanes. I read some say that it’s supposed to. Though “supposed to” and usually does in practice are two different things.
See this thread for more talk about potentially using different displays: Different battery and display (smaller)? Note that Arya in that thread is the one who wrote the link on Common eDP pinouts (part of the All About Laptop Display Reuse info resource).