If you have MS Office installed, it comes with viewers which work in the Opus and File Explorer preview panes.
If you're looking for something that lets you view those formats without Office, the only options I know of are older versions of QVP or, with the appropriate DLLs, MultiView viewer (various document formats)
Hi, I tested Directory Opus with Quick View Plus 2020 and it works just fine. One .docx and one .xlsx File created with Word 2019 and Excel 2019. You don't need older versions. But I had to pay $99 for a one year license. It's a rip off.
