Missing context menu entries (Opus & Explorer)

Hi, now and then it seems that this problem arises...
Some time ago, when in DO I right-clicked one or more doc files, the context menu showed the options to combine those documents into a pdf file. The same in File Explorer. Now the pdf-related section of the context menu is disappeared when I right-click an Office file like Word, Excel, or PowerPoint. In reverse, it is still there if I right-click a pdf file. This may seem quite obvious but it isn't. Yes, because I have Acrobat Pro installed on this PC, all the PDFMaker-related options should be in the context menu.
At the same time, in the new file/folder section of the menu, I find the new Google sheet, doc, slide entries, the new txt file, the new Access Database, the new Project document, the new Publisher document, the new RTF document (and more) entries but the new Word, Excel, PowerPoint documents entries are missing. I would have been less surprised if I hadn't found any Office entries. On the contrary, some are there (new Access database, and Publisher document entries) and some are not.
To tell all the truth, my installation on this PC is quite old. I am confident that if I make a fresh installation many oddities would disappear. The problem is that a fresh installation of the OS and software would require two or three days of machine stop and I can't cope with such a long time of inactivity, in addition to the cost of the technician for the intervention. To say it better, I would like to exclude that this can be the only solution. I already tried to reinstall DO and Acrobat without success.
Any idea? Thank you in advance. Regards.

Are these menu items all in File Explorer or missing there as well?

They are missing in File Explorer as well.

Can’t be an Opus issue in that case.

If reinstalling the software the menus come from doesn’t bring them back, it would be best to ask the people who make the software.