More topspin shots doesn't mean better shots. Graf hit a heavier slice than all of today's men. The amount of spin you put on a ball has nothing to do with its pace. It only slows the ball down. Any woman could hit topspin groundstrokes like a man if they wanted to. Thing is, they don't want to. They hit error-prone, flat(ter) tennis because that's their choice and the result of their coaching.If you believe that UTR is accurate, the WTA #1 Ash Barty has an UTR of 13.36 which is similar to ATP players ranked around 1,000. Novak Djokovic who is #1 on the ATP has an UTR just below 16 currently.
Having seen many ATP and WTA tournaments at all levels in person, I think that the Challenger/Futures level ATP players ranked between 800-1,000 do seem to be on par with top WTA pros and many of them get jobs as hitting partners for WTA players after they give up their dreams of making it on the ATP tour. The most obvious difference you can see between the top men and women are related to movement and serves - the men move much faster to play better defense and their serves have much more topspin at 10-20mph higher pace on average with the difference being greatest for 2nd serves. On ground strokes, you don’t notice much difference in pace, but the men hit a heavier ball with much more topspin.
If they played points off baseline feeds without serves and returns, I suspect that the top women might be closer in level to ATP men ranked around 500.