With all the postprocessing done to smartphone photos now & what we subjectively consider to be a "good" smartphone photo, the positive effects of large sensors are largely negated. Just as a lot of the downsides of smaller sensors are eliminated by this postprocessing, it has the reverse effect on larger sensors. The only benefits these massive sensors like the Isocell GN2 have over smaller ones are in low light because of this. Shooting raw vs processed on my Pixel 6 (GN1) I was floored upon seeing the kind of photos I was missing out on.

Sensor might be big, but the software on xiaomi 12 is just crap. check out reviews.

I recently had both Pixel 4 XL and Xiaomi MI 11 Pro. The latter phone has the large GN2 sensor for the main camera.  I terms of sharpness and details the two phones were fairly even. However, images from P4XL had a lot more noise in low light situations. All in all, I still think the camera on P4XL is pretty great even tough I sold it due to Mi 11 Pro being a much better phone overall. As descriped in the article, camera software are the most important factor (not hardware). I think 12 Pro would outperform P4XL since Xiaomi seems to have improved their camera algoritms in their 12-series phones. Comparisons betwen Mi 11 Ultra och 12 Pro indicate that 12 Pro takes better stills despite the smaller sensor.