Slot sizes are mostly including the back plate.
A normal 2 Slot card is 2*19,75 = 39,5mm (inlcuding the back plate)
A 2.2 Slot card is 2,2*19,75 = 43,45
So I think the new 2.2 Slot EVGA RTX XC3 will fit.
According to this post by EVGA it's 45.1 mm with backplate (XC3 Ultra/XC3) and 40.9 mm without (XC3 Black) - that's a bit above both limits listed in specs.
What about the Zotac RTX 3070? The specification says it's 41.5 mm and on the images it appears to have a backplate (?). Is it going to fit?