So, this is for sizing on the Vaporfly's:
Mostly because I see many on here refer them as large in sizing, that is however not the case!
What you are experiencing are the more real to life shaped toe box. When you run and hit the ground the foot expands, and cramped toes will damage the foot, thats why they are made wider than lifestyle shoes.
Strangely they are still not "wide" fitting to me, they are just wide for being of Nike. Their lifestyle shoes are all way too narrow! I get a space in front of the toes, much like the way you are supposed wear a condom, but shoes are not condoms!
And with a larger drop shoe, your toes will, for the first time, be able to reach all the way to the front of the shoe when your foot slides forward. The heel slippage sensation will be a fact.
I got the SP's, they fit too tight really, but wearable with super thin socks.
I got the Vaporfly's in the same size as the SP's, they fit a tad longer (not a full half size longer), but wider and more flexible than the SP's.
I also got the Vaporfly's in a half size larger than the SP's, and these are the best fit of a shoe that I have ever worn! I will use this size as a reference in the following comparisons.
References:
Nikelab Zoom All Out Flyknit's in a full size smaller fits longer but more narrow compared to the Vaporfly's
Spiridon Ultra's in a full size smaller fits longer but more narrow compared to the Vaporfly's.
Nike Lunarepic Flyknit's iD (Wide) in a full size smaller fits longer but still more narrow than the Vaporflys.
Nike Airmax Zero in half size smaller fits longer but more narrow than the Vaporflys.
Just a few examples, but my point is that they are not larger in size than any Nike's. It's more like the other way around, they fit small, but wider!
The ZoomX is going to change things! This is the first shoe ever that feels like a true extension of my body, working in a conjunction and really helps me instead of stagnating me!
And as for the material - I see no need for Flyknit, the Technical Mesh has the perfect shape, soft feel and amount of give. And it is probably a lot lighter than Flyknit. But sure, ZoomX soles with Flyknit version shoes would be nice to try.