13" is a great size for a truly portable use case.
I find a 'standard' 13" (as on an older Macbook Air, for example, which I think is technically 13.3" and 16:10?) a bit too claustrophobic for anything creative - either due to apps needing toolbars, or my workflow needing multiple windows accessible (e.g. coding, with VSCode, a shell or two, and a browser for docs and StackOverflow).
A 15" (which I have now) is nice to work with, but then the laptop becomes a touch too heavy for travelling comfort (unless this is something you specifically optimise for when buying e.g. [0] - but then there are other tradeoffs).
Thus I wonder if a 14-14.5" with minimal bezels, set in a lightweight chassis similar to a traditional 13" (see how big the bezels are on an older Macbook Air, for example - lots of space for a larger screen without unduly enlarging the chassis) might not be a sweet spot?