You can adjust the Pro 14 resolution to some degree. But it won’t look as good or be as easy to read as the MBA 15. Also if someone was adjusting screens the could adjust the MBA 15 screen and get even more working real-estate than the adjusted MBP.
I have a MBP 16 and I prefer my old MBP 15 screen better. I can’t stand the halo-effect of the MiniLED. I never notice the Promotion. I rarely watch HDR. I don’t notice the supposed advantage. The avantages of MBA 15 over MBP 14 include being slimmer, better form factor, quieter, lighter, less moving parts, less dust, cheaper, bigger display, no halo-effect, higher default scaled resolution and usually better battery life (but maybe the base M3 can compete)
RDM won’t really fix the problem. If you make the resolution too high things will be too hard to read on the smaller display.
The MBP are more powerful machines and some people might get value from that. But for the majority of people, the M2 is more than fast enough. And some people will find value in the bigger display and be better off with a MBA 15 or MBP 16.
All I’m saying is if your gonna recommend someone looking at the MBA 15 get the MBP 14, make sure they are okay with going back to a MBA 13 size screen.