Question about Samsung Galaxy S22

Gorilla glass was used for the entire S22 series, i.e. S22, S22+ and S22 Ultra. The back cover of the S21 was made of polycarbonate (plastic), but this is no longer the case.

The back is matt glass, the frame (unfortunately) polished aluminium. The back may be more valuable than plastic, but glass can always break. Unfortunately, the manufacturer is happy to accept this (as a (re-)sales-promoting argument, broken glass = I need a new part... the glossy frame is supposed to imitate the expensive iPhone Pro, but I hope the fingerprints are less visible because of the curves.

Correct, the exact material designation for the back cover is plastic :-)