[Question] I wonder which champs should I buy....

I'm going to ranked pretty soon and I can't figure out this dilema I got right now but maybe some of you can help me out with the decision, I'm saving up some shards and essence so I don't rush the purchases.

I mainly play mid and jungle sometimes the other way around, and I was wondering if I should buy some broken midnalers and junglers OR I could also buy some decent ad carries and win us the game by not being the botlane that let's the enemy adc double in farm and give it more than 10 kills to both enemy botlane and jungler if he comes....

So I'm asking which buy would be more worth and if it's even good to switch to adc since it's a duo lane and sometimes the supports are just not good or even terrible to be honest but maybe some adcs don't care that your support doesn't play optimaly and carry anyway.....

Thanks.