I booted up Office '97 on a Win 11 computer cause I needed to access an Access '97 document for work. Office '97 still works pretty well. Clippy even took over my desktop the same way he did in '97, it didn't look quite right because I guess borderless windows work a little different than they did almost 30 years ago but it worked.
I don’t think they made any real improvements after Office 97. It had all the features of any value and none of the weird fluff or changes for changes sake.