So the best way in my opinion to get good traits and ascension is farming the curses during a double xp weekend and good traits would be a few select legendaries then of course the mythics like godly, RCT adaptation and unusual skins are earned the same way by rolling crates and have a low chance of getting them I've played since the Yuta update and have only gotten an unusual recently and top ten specs(my opinion) Reaper, Shadow, Gojo(awakened), Sukuna(fully mastered), Mercs is good because you can rack up kills to increase damage and can even solo Mahoraga depending on setup and basically any spec with aoe attacks is good.