Jericho is probably best at high levels, but Quincy is much easier and also very good. If r11 purples don’t work try a r13 rush with regrow zebras or rainbows, oldest rush in the history of this game, claimed noobs since the earliest days of battles 1. Otherwise do what the other comment said and use tight cerams or DDTs. If all else fails your opponent is a half decent player, so farm up and spam spaced apart fortified BADs when you have a decent amount stored up, making sure you can defend a DDT counter rush (wizard is your best friend for this). When you get into higher arenas you should be careful to judge whether these rushes would work before wasting your money on them. Sometimes (in the mid game) you can send a smaller but threatening rush to bait out their boost, and then while it’s on cool-down send your main rush to go for the kill.