The reading problem
See whether the reader can still reach every line and control.
A concrete example
A sidebar that looks tidy at full desktop width may collide with a paragraph at high zoom. The important question is whether content and actions remain available, not whether the design remains identical.
Try this edit
Enlarge text, narrow the browser, and move through the page with a keyboard. Record clipping or sideways reading as a fix to make. Do not treat the Paragraph Measure preview as a substitute for testing the actual page.
Proof on the page
Open a page with a text sidebar, zoom the browser until the reading column collapses, and note the first point where two-dimensional scrolling appears. Move focus through every control in order. If the sidebar overlaps the paragraph, let it stack above or below the main text. Repeat with a long unbroken URL, because short sample sentences may hide overflow.
Where the method stops
The Paragraph Measure cannot run this inspection for your page. W3C reflow and resize-text criteria concern content and functionality in the actual interface. Browser zoom, text-only enlargement, responsive CSS, and embedded documents can behave differently. Record the viewport and failed element so the real implementation can be fixed and retested.