Ekeler is a good change of pace back while Justin Jackson the 3rd stringer is more of an every down or early down back
While it's true that ekeler has thrived in the 3rd down role he has struggled immensely as the early down back when melvin Gordon has missed time. Conversely Jackson has done well when given the bell cow role in Gordon's stead.
Comparing Jackson to ekeler is comparing apples to oranges. They technically play the same position on paper but their actual function in the playbook and gridiron are very different
Jackson is not bad but Ekeler a big time receiver, Woodhead type. Ekeler might be the only RB in NFL history to average 5 ypc and 10 per catch career obviously low sample but he is impressive.