It’s quite difficult to argue about tactics and strategy without a specific situation and task. But we shouldn’t forget that the goal is not to collect more artifacts, but to defeat the enemy (although collecting artifacts also contributes to this). Victory over the main hero (no matter how it is achieved) is already half the battle. Moreover, the option I proposed is used against very strong enemies, whom you simply cannot defeat on the battlefield. And this plan is implemented quite quickly.
In my understanding, middle-tier heroes don’t engage in collecting; they defend the areas that haven’t been captured yet. And, of course, they collect those with only one harpy:D
Just for fun, take a look at my map posted on this site. There are plenty of enemies to fight there;)