As mentioned here, the above-requested feature has been implemented.
At first it didn’t work for me, but then I realized that Obsidian was choking over the extra spaces between - and # which Dynalist generates (export > Formatted, copy & paste into Obsidian). When - and # are separated by only a single space (as happens when I use the dynalist-to-obsidian tool referenced here), Obsidian displays the bulleted heading correctly in Live Preview mode (as it already does in Reading mode regardless of the number of spaces).
(Ideally, the developers would make Obsidian more flexible about the number of spaces it expects between - and #, and/or tweak Dynalist’s export format so it generates the number of spaces Obsidian requires – apparently 1 – to correctly render bulleted headings in Live Preview mode.)