I think we need to wait for M3 to assess their progress. We don't have enough info. yet.
Like you, I'm also a fan of desktops. I'm most affected by SC CPU performance, and there the Mac desktops have thus far, on average, compared favorably to high-end PC's, particularly when you factor in their efficiency and its benefits (esp. quiet operation).
For instance, when the M2 was released, its GB5 SC score was within 10% of Intel's fastest enthusiast desktop chip, the i9-12900KS, which had been released just two months before. [According to GB's benchmark charts, the M2 (released June 2022) and i9-12900KS (released April 2022) have GB5 scores of 1899 and 2083, respectively.] Getting that close in a much quieter and more efficient machine seems like a win. Having said that, I would like to see Apple push SC speeds somewhat more for its desktop machines, if they can do it while maintaining quiet operation.
Where we see much more of a gap, particularly at the high-end, is in GPU performance. I assume they're working actively on that, but we shall see.