I think that the decision to make a piece of fingering text a property of a note is correct, since each fingering item relates directly to a specific note in the real world. I am sure that an easier method of input can be added to Dorico at some point. I’ve managed to use AutoHotKey to speed this up considerably on my PC (it behaves in a similar manner to lyric input) and I believe there are similar macro programs available for Mac.
Here is a link: