It’s quite common in MT (Finale?) templates to have bar numbers that don’t ever try to avoid collisions. Presumably this is applicable to other genres too. For example like this:
At the danger of making assumptions and telling developers what to do, I wonder if, rather than making it possible to select multiple bar numbers in order to quickly fight the software’s collision avoidance, it might be worth having a Layout Option that just tells Dorico to put bar numbers exactly x units above/below the staff? It would be up to the user to get the final tweaking right, but in the case of the OP, certainly, it would result in significantly less manual labour. I daresay it wouldn’t be easy to implement, but it might be easier than implementing a “select more” function for rules-generated items.