Thank you for your input.I had exact the same question. And for my research - M2Pro in HQ mode has a bit more detailed image than M2Zoom at 40mm. But if you want to compare M2Zoom at 48mm, you have to digitally scale M2Pro HQ footage by additional 20%. And in this case M2Zoom becomes a bit cleaner, since it's completely optical, but still very similar with scaled M2Pro. All depends from digital scaling algorithm you applied to M2Pro. But again, the level of details and sharpness are VERY similar even after 20% digital scaling. And if you're ok with 40mm instead of 48mm, then you can use HQ mode without additional digital scaling, and it will give you sharper results than you could achieve with M2Zoom at 40mm.
I picked M2Pro, because I don't need to zoom while I filming, and HQ mode gives the same "cinematic" perspective compression (so it's not an exclusive "feature" of M2Zoom), also we gain 10 bit, D-Log and much better low light capabilities (thanks to constant f/2.8 aperture and 1 inch sensor)
You can find good comparison between M2Z 48mm and M2P HQ mode in this article: DJI Mavic 2 Pro VS Mavic 2 Zoom: The Ultimate Comparison | MyFirstDrone
From what I've managed to find on the forums and watching youtube reviews I kind of expected that could be the case. Unfortunately I couldn't see anyone testing this even though there seems to be quite a few people having the same question. I had no doubt that Pro would outperform Zoom in low light. I thought that maybe in good light the Zoom could actually resolve a bit more detail even though it's still using smaller portion of the sensor albeit with more pixels. The link you provided proves it's not the case, really.
Cheers.