Meee. Are you talking about resolution scaling? It's meant to normalize what you see to help keep things readable on higher-resolution screens, but folks at 100% scale are more likely using lower-res screens so your site would look normal to them (is my understanding).
Hmmmm I think so? i have a high resolution screen and if i put it on 100% everything is way too tiny to use it comfortably so i just kept it on 125. but yeah that makes sense, I looked on my laptop and it kind of looked the same even though that one is at 100%
thanks!!