Are you using the current version of Word (16.101.3)? Running that on Tahoe, using Save As... and selecting PDF works for me on Tahoe 26.0.1.

Note that there are two options with radio buttons, 'best for printing' and 'best for electronic distribution'. @KiltedTim, the second one of those is one reason the Save As PDF option is necessary for some people. With that option, for example, if you have a ToC or index in the document then the entries in it are live links within the PDF document, not the plain text you get with Apple's PDF engine via the Print dialog. Personally, I pass on that option in Word because it routes the file through Microsoft's servers and thus when I select that option I get this:

After hitting Cancel, then I get a popup that the document could not be saved.