Apricots small and hard and never ripened
We have 5 apricot trees. Last year was the first year to flower and the fruit was really small and it stayed hard until it fell off the tree, never ripened.
Fruit trees usually need a certain number of years to develop sufficient roots to support a healthy crop. This may well be the main reason your young trees dropped their fruit. This article tells you more about fruit drop: https://www.gardeningknowhow.com/edible/fruits/apricots/apricot-fruit-falling-off.htm
Meanwhile, this article will help you to keep your trees as healthy as they can be: https://www.gardeningknowhow.com/edible/fruits/apricots/apricot-tree-growing.htm