I upped the font size on my Pixel recently and this is one of those sites where (in Firefox) the sidebar takes up more than 50% of the width of the screen and retains tiny text while the article itself wraps on a couple words per line.
Mentioning these things in a comment is neither accepting of how it is nor changing it. You can't change the site - the author died. You can change your browser or reading mode or whatever. Or you can just accept it is the way it is.
I see you noticing a thing, with your senses. Sincerely:
A (used) folding phone offers 66% body content, 33% sidebar. Is a noticeable improvement.
I don't want large phone though. I'd prefer to have a less appealling small phone that encourages me to spend more time off it.
I'm willing to switch between Chrome and Firefox. On Chrome I get 66% body content I can't read. It's one of the reasons I stopped using Chrome.