Well, the peripheral area at 24mm looks quite a bit softer, even if you drop the new lens to the matching f/4. At 16, 20, and 28 though, yeah, not a significant difference in sharpness. They're not shot with the same body either R5II vs R5, so who knows what to make of it. The 15-35mm is also shot w/ R5.

I'm waiting on the James Reader shoot-out video, assuming one's coming, since his 28-70 comparison video was one of the most thorough comparisons I've ever seen. Not waiting too impatiently though, as I'm not sure I need such a wide lens... I rarely use the EF-S 10-18, and this is basically the full-frame version with a faster aperture.