What champions are best for climbing after 100 games

I've been playing the game for about 2 years now and i'm finally wanting to start climbing the ranked ladder. Currently my ping is usully 40 but can spike to 1000, although the spikes usually only happen a couple of times and for a few seconds. I'd prefer not to risk losing the game because I lag during a baron fight, so until I can get stable internet in a few months I won't be starting ranked. Since I've got some time on my hands I want to learn a more difficult champion. I could just play Annie but she'd get boring pretty fast for me and I want something less static.

For context I mostly play mid but i'll play any role except jungle. It also doesn't have to be a carry champion like lee sin or Riven. It could be a champion that climbs through decision making and utility like thresh. I also don't know where i'd place myself in terms of elo since I've never played ranked.

Thanks in advance for the responses.