What gaps between screenshots in AppStore for each type of device:
Probably, for:
6.7" 1290 x 2796 = ?
6.5" 1125x2436 = 107.25
6.1" 1179x2556 = ?
5.8" 1125x2436 = 52
5.5" 1242x2208 = ?
4.7" 750x1334 = 39.5
4" 640x1136 = ?
Am I missing something, or there is any guidelines or answers somewhere...
Welcome to the forum.
I'm not sure to understand your question. What do you want to know ? What is after the = sign ?
In any case your figures are wrong. For instance
6.7" 1284 * 2778
6.5" 1242 * 2688 (in fact 6.46")
Get all figures here: https://www.ios-resolution.com/