Web page annoyances that I don't inflict on you

The page is so narrow, like it's made for a vertical smartphone screen. That's ANNOYING!

Look up any typographic manual and you'll learn that you can't make lines of text too wide or else people will have trouble reading them. Example - https://practicaltypography.com/line-length.html .

This is also related to why professional newspapers and magazines lay out text in relatively narrow columns, because they are easy to scan just top-down while hardly moving your eyes left-right.

I do think that vertical phones are too narrow for conveying decent text, but you also can't have completely unbounded page widths because people do run browsers maximized on desktop 4K screens.

That research may be true, but the layout of the page should be up to the user, not imposed by the developer. If I want my browser to display a web page using the entire maximized 4K browser window, that should be something 1. I can easily configure and 2. web developers respect, no matter what the "typographic researchers" think.