It does not really tell us much, but it is interesting to note that at its best, all cameras can focus at 0.02 sec. A limitation that is given by hardware (moving the lens elements etc). And of course the X-T4 of course lacks of subject and animal tracking features.
Other than that, whenever something is moving, the Fujifilm X-H2S has the upper hand due to its stacked sensor design.
However, there is one aspect, where the Fujifilm X-H2 beats the Fujifilm X-H2S, and that’s “high frequency subject“. The reason for that is simple and Fujifilm explains it below.
X-H2’s higher pixel count increases the number of phase detection pixels, which improves AF-S focusing accuracy on subjects including landscapes and portraits. The camera also incorporates an improved AF prediction algorithm, newly developed for the X-H2S, enabling stable focusing even when using AF-C. The X-H2S excels in moving object tracking utilizing the performance of the stacked sensor, while the X-H2 excels in accurate AF for static subjects.
So there is an advantage also in having many more phase detection pixels packed closer together into a higher megapixel camera.