I'm kind of confused about this - I'm sure the author experiences real problems, but I wonder if there's something else at play here?
I've never actually seen screen aspect ratio media queries used in practice, nor have I really seen them advocated for. When I load www.theguardian.com on my portrait monitor (1441 x 2561) I get the desktop layout https://imgur.com/a/ZpUI95Z
Absolutely yes design your breakpoints around screen width. Using aspect ratio seems like a poor choice.
Even then - when I set my resolution to the same 1080 × 1920 the author states, The Guardian still renders the "desktop" layout. The more compact layout from the doesn't kick in until 739px.
Maybe it's their font-scaling settings are getting in the way and changing the viewport resolution?
I've never actually seen screen aspect ratio media queries used in practice, nor have I really seen them advocated for. When I load www.theguardian.com on my portrait monitor (1441 x 2561) I get the desktop layout https://imgur.com/a/ZpUI95Z
Absolutely yes design your breakpoints around screen width. Using aspect ratio seems like a poor choice.