Chose my main role

Hi guys, i have a plat 1 accaount and a plat 4 account: 17WARREN17 and MY DAD IS RIO CEO. I create this topic because i want to become at the game cause i'm plat xD. I want to claim to diamond (lost my promos d4 recently) but i have an issue. I dont have a main role and most players in "high elo" have a main role. I can play Top Jungle Mid or Adc in plat and have a positive win rate but now i want to definitely chose a role. Top: I have less games at top than jungle and mid but i have a good win rate on Jax Fiora or Mundo. Sometimes i like playing top and sometimes not. Jungle: I starter league by playing jarvan jungle and it's my main champ even if i don't play him since 6 Month. Jungle becomes boring to my mind because of my champion pool but i am a bit better in jungle than other roles. Mid: 2 seasons ago i started playing mid with Casisiopeia/Vel'Koz (Sardoche viewer xD) Karma/J4 ad and Brand but i didnt play a lot mid lane these times. And i dont like playing assassins like ahri/Kata/zed/akali and i know mid laners of my elo have a lot of xp on these champs so even if i start playing them i'll be bad. But i can still play Cassio/Vel'Koz or even J4. Adc: 1 season ago i was a very bad adc (i dont say im good now but better) and didnt have any expérience on this role. But last 6 months i played a lot of Sivir/Caitlyn/Kog'Maw/Jinx/Twitch games and i quite like this role. I am ok in laning phase but i am not good in mecanics compared to plat 1 adc mains because they have like 10 Times my expérience on this role and his champions. I have good dmg dealt at the end of the games but i feel like i don't play team fights as i should play them so sometimes my team flames xD.

I hope you guys can help Me to chose my role because i am a bit lost i must say. I need 1 or 2 main roles to really improve in elo.