Are the Fingerings for Fretted instruments not what you want to use, which is why you are using Text? (I was thinking if you used them, there might not be a problem, but you might have already tried it and prefer manually adding them as text.)
If you use normal fingerings with the Shift+f pop-over, Dorico does a pretty decent job. For strings outside the staff, use the Shift+p for strings (string 1, 2 etc.).
You can try under Library → Font Styles. There are Fingering entries. There are also Scale-factor settings in Library → Engraving Options → Fingering → Fingerings Inside the Staff.
I’ve never played with either of them though, so good luck.