The 45W rating is hardly relevant. Excluding Apple, Intel 11th Gen Core CPUs are the fastest on most single-threaded benchmarks, whether they are configured at 15W, 27W, or 45W. In fact there is barely any difference in peak performance between the 15W and the 27W config.
That's the single core improvement you have between Zen 2 and Zen 3, but Zen 3 also has sightly better power usage than Zen 2 and Zen 2 was already superior (allegedly - I haven't actually used a Zen 2 mobile device since nothing really premium was built with it) - Zen 3 mobile isn't out yet but I suspect it's going to be a much better experience for mobile just like Zen 2 was compared to 10th gen intel.
