For me, it's more like "reading mode on Firefox makes the web usable" on all devices.

For my fellow Android users out there, Firefox also has a reader mode.

https://outline.com if reader mode not available -- works in pretty much any (JS-supporting) browser.

A small set of sites fail to render, including Google's Blogspot, using dynamic themes, which are abominations to the Web. No "fix this site's fucked CSS / styling" tools seem to be able to handle that.