Here’s what I’m getting with my defaults:
I think Dorico is scaling the parentheses to the slash size in your lower example though, and it seems a bit larger than the other elements, so is getting an exaggerated result. Since Dorico doesn’t really offer much control over the slash size and positioning, I created a doricolib file that will add a functioning “Chord Symbols Slash Font” Font Style. I posted it in this thread not too long ago.
If I increase the size of the slash, I get an exaggerated result like you are seeing:
The doricolib file also allows default scaling and Y positioning (positive values are down), so you might want to try playing around with it and seeing if you find settings that work with your fonts.
<component>
<componentId>glyph.bass.slash</componentId>
<componentType>kGlyph</componentType>
<xOffset>0</xOffset>
<yOffset>0.5</yOffset>
<xScale>125.000000</xScale>
<yScale>125.000000</yScale>
<zOrder>0</zOrder>
<maxOpticalScale>100</maxOpticalScale>
<componentInstance>0</componentInstance>
<colour>kDefault</colour>
</component>