I finally found the words for the design theory I’m chasing. Intrinsic Web Design. First presented at a conference in my town 8 years ago, but I’m catching up.

I’m avoiding breakpoints because they’re too rigid and don’t take variables. Grid columns and flex items can. Changing breakpoints requires regenerating your css. Setting variable values could be done in the UI (via UI Skins).

I’m trying to balance widths set by the layout with the intrinsic width of content.

https://justcreative.com/intrinsic-web-design/