Heres actual data from SpainYou can't sell what's not on shelves. And people aren't not willing to spend 300 to buy something they don't want;
https://www.resetera.com/threads/playstation-sales-news-and-discussions.393232/page-6#post-76891638
From about week 10 onwards, you can buy a series S ( they have been near constantly in stock), the series X or ps5 has never been in stock, i.e. they sell out immediately.
So the following numbers show the upper bound of what the series S will sell, looks to be 1000-2000, but we still dont know the series X true demand as theres not enough stock to satisfy demand.
Next week may show a large jump for series S (black friday here in spain & the series S had a 10% pricecut to 270 euros. Series X and ps5 no pricecut)
Worldwide the series S should do decent this xmas as its the only next gen console avialable, by the middle of next year when the series X becomes more available, demand for series S will drop.
Even MS's biggest flagship title isn't doing what it was meant to, i.e. display the same game but just at lower resolution (halo infinite seriesX=120fps, series S=60fps)