The FAQ of dvisvgm mentions the following:
The generated SVG is most likely valid but your SVG viewer/editor
probably doesn’t support embedded fonts. Actually, only few SVG
renderers, e.g. Apache Batik and the Opera web browser evaluate
embedded fonts properly (also see the screenshots). You can run
dvisvgm with option --no-fonts to replace the fonts with path
elements. Most viewers should render the resulting SVG files
correctly. As a drawback, you get bigger files, and the information
about the text (characters, baselines, …) gets lost.
As of version 2.0, dvisvgm provides the command-line option
--font-format that allows to change the format used for embedded fonts from SVG to WOFF, WOFF2 or TrueType. If you call dvisvgm with option
--font-format=woff, you should get SVG files that render correctly in almost all recent web browsers. Moreover, and in contrast to option
--no-fonts, all text properties are retained.
Indeed I could reproduce your issue with Chrome, but with WOFF the output was correct.
MWE:
\documentclass{standalone}
\usepackage{DejaVuSans}
\renewcommand*\familydefault{\sfdefault}
\usepackage[T1]{fontenc}
\begin{document}
\fontsize{9mm}{10mm}\selectfont
{\bfseries aceimnorsuvwxz}aceimnorsuvwxz
\end{document}
Command line:
dvisvgm --font-format=woff xdvconv.xdv
Note that I used version 2.8 of dvisvgm, but according to the FAQ it should work with earlier versions as well.
Result:

--font-format=woffand--exact. See https://tex.stackexchange.com/a/469440 – AlexG Nov 10 '19 at 21:10