The `Line Breaking` functionality is indeed limited, it is not dynamic reflow for all the reasons I noted [above](https://github.com/geany/geany/discussions/3718#discussioncomment-7837294). Perhaps in your use-case you might be better off doing `Edit->Format->Reflow lines/block` on a regular basis rather than single line breaking so the whole paragraph is handled.
Also be aware when gathering data from random websites that counting columns on reflow does not account for combining characters so `öööööööööööööööö` will count as twice as many "columns" as glyphs. Same for version selectors on emoji and for double wide Asian characters (which count less than the glyph width).