You can't say that with certitude.
iPhone 11 was the best selling iPhone mainly due to attractive price + average consumer is not that interested by OLED. The size was not the main reason.
If 11 Pro and 11 size were swapped do you really think the 11 Pro would be the most sold iPhone out of the 3 ?
At this stage no one knows for sure.
If I had to guess I would say both non-pro models will outsell Pro models (like the XR in 2019 and 11 in 2020) once again because the price is more accessible for average consumer while having a close look/features vs Pro models. Remember that we are not reprentative of the average consumer since we are in a Tech/Apple focused forum

It's normal that people here on MR is more willing to get the best/newest models vs average.