Desktop Site Version Responsiveness Issue

Hey Squarespace. I am a graphic designer, who works primarily with SS Sites, and I am contacting you on behalf of my client's website, and it's responsiveness to the DESKTOP version of the site. This is somewhat of an urgent issue since we are working with deadlines, and I need any and all help that you are willing to offer!! Thank you in advance!! I have built many sites in the Brine family, starting with the Miller Template and then always deleting everything in the template and starting completely from scratch, always going about it the same way. Sometimes, my websites translate EXACTLY how they look on my Laptop, to the Desktop. The spacing, the text sizing, all of it looks the EXACT SAME. Which is how I prefer it! :) However, sometimes, like with this current site I am working on, the template completely translates weird, and the spacing is thinner and stretched, photos and text appear smaller, and the spacing of the menu header is off. Is there at all any possible way or code or anything I can do to essentially "lock in" the style we work so hard on, in the editor, to translate correctly on 27in Desktop computers? Does this make sense? Thank you so much! The first attachment is what the site looks like on Laptop (what I want it to look like) and the second is how it's showing up on Desktops. ( What I dont want because the spacing of the header and the cropping and spacing of the images is thinner and off!)

Can you share site url? We can check easier.

The site is not yet live, but here is the password protected URL. Password is 'example'

conch-opossum-6tmx.squarespace.com