Sometimes, even Word has a challenge opening .docx documents and if Pages detects something in a Word .docx that it cannot translate into Pages internal document format, it too may refuse to open the Word document.
The trusty fix for this is to use the free LIbreOffice Suite to open that .docx and then resave it from LibreOffice Writer. Then open that .docx in Pages. If LibreOffice cannot open that .docx, then it is damaged beyond repair.
On the LibreOffice 7.5.n download page, note that the selector offers macOS (Intel) and macOS (Apple Silicon). Make the right choice for your new M2 architecture MacBook Pro. It is what I use on my M2 Mac mini pro. Once you have installed LibreOffice, visit the /Applications folder, right-click on the LibreOffice icon and choose Open. You only need do this once, or with future LibreOffice updates.