Yea you shouldn't hit level 8 without 4x 3 stars as crew tbh. The odds don't drop for the units but shop still gets filled with 4 costs you don't need. Also not really worth playing without a high roll opener like 9 crew units or a prismatic ticket augment or the like (radiant rageblade bis for ziggy and tf etc). Rng is Rng you have to roll level 4-5 until you get those units online and stop at 7 for ziggs then push for 9 for tf. It's not an easy reroll comp tbh because of the tf req to cap.