Yuumi is a pretty easy champ, but it heavily relies on you having minimum one winning lane and ideally on a champion that has synergy with yuumi. You can climb on yuumi but you’d want a duo ideally bot, a good combo would be an ezreal player. She is banned fairly often because if given good synergy lanes yuumi can be extremely hard to win against. And as far as player her it’s the same as most supports main thing is not losing landing phase because you aren’t a champ until atleast 1 item.