Something I noticed very quickly while assembling the bike is that it has quite a bit of flex around the bottom bracket. I think the horizontal stiffness is limited because of the narrow down tube. I have to admit that I also notice this when sprinting >1000W on the road, and I don’t particularly like it. When riding normally in the saddle or out of the saddle, I can’t really feel it. You can already see it if you tilt the bike slightly to the side and then put some load to the pedal, you can see how the frame flexes. Significantly more flex compared to my other bikes. In the future, I’d probably make sure the tube shapes are designed for high stiffness.
Edit: I have the Superlight… I wouldn't go for the Ultralight, as that would only make the stiffness issue worse.