Only thing I know is the weekly mission gives a guarantee one I believe but that just a week and I barely made any progress on Lightfall weapons. I don't seem to get jack from doing Terminal thing and doing regular patrol and Lost Sector gives me no loot (why is that even a thing with LS?). I like to get a hold on as much craftable weapons I can but it only this and the ones in Riven's inventory (Not the Wish weapons but the other ones look like moss vex-like weapons). I don't feel like doing anything else but to farm for craftable stuffs. Seeing loot from Onslaught makes me appreciate many craftable weapons much more. Also it's bad when shiny ones get double perks to choose from the final 2 slots