Speaking of my own history with operating systems and respective systems, our originally family computer circa 1997 was a Pentium MMX 166. This had Windows 95 on it at the time.
Some time in 1998, I bought my first PC of my own, an AMD K6-2 333MHz. This likely would have had Windows 98 at the time, since I probably bought it in the latter half of 1998. I don't recall off hand whether our existing family computer would have also been upgraded to Windows 98, but it probably was at some point. But at that point, I was using my own AMD PC.
So I most associate my AMD K6-2 build and subsequent PCs with Windows 98, not Pentium MMX systems.
Which also goes back to the point of this project. I had previously built a re-creation of our old family PC circa 1997. The intent of this build was a theoretical 1997 build to see how it would have compared. Hence the 'fantasy' in the title of the thread.