I don't see this rumor as anything more than wishful thinking.
Those screens at that size is something Apple would charge no less than $3,000 on top of whatever computer is attached to it. So basically a screen that big and expensive with the equivalent of something no slower than a Macbook pro connected to it. So subtract the price of the macbook pro screen and you have the base configuration of the iMac with that screen. What is that? $4,000 minimum? Thats a pretty big jump from a line that will start at around $2,000.
The new iMacs will probably range from $2,000 all the way up to $3,000 and not have the best screens, just better ones than the current iMac and almost as good as the current Macbook Pro's, probably the same kinds of screens the M2 macs will come with standard.
The real iMac Pro with true XDR screen will probably come after the Mac Pro introduction.
I think after Apple comes out with its Mac Pro chips, you will someday be able to configure iMacs that cost $6,000 - $10,000 because you are putting in top of the line Mac Pro chips in them and it will come with a true XDR display with a matte glass finish. Things that are very pricy today but do not cost Apple a lot to produce so when they seeminly lower the price down to fit in an iMac. It would look on the surface as a cost savings to the customer but really a way to let Apple raise the price of an iMac to a level people would not have tolerated before because now you get nano texture glass, XDR display and Mac Pro speed chips thrown in for less than getting all that in last years intel Mac Pro. Great savings for the movie studios and future VR content producers that will be able to fully utilize them.