Chordsymbols: size of (superscript) accidentials

In chords I want accidentials of root notes to be displayed as superscript like in this example:

For my opinion, Dorico renders them too small by default:
Maybe I’m missing something, but I can’t find an option to change the size.
I don’t want to tweak every chord by manual overrides.

Have you tried the different chord symbol presets? (not exactly what you are looking for, but you might find a different format acceptable).
(Engraving options>Chord Symbols)

That looks more like a font issue that came with 1.2. Daniel has posted a fix on the facebook group, which you’ll probably find with google if you need it right now. I would guess this fix will be included in 1.2.10 which is supposed to be released in a few days.