There are definitely issues with ranked play, but if you belong at a certain rank you can get close to it. Not every gold player can carry to gold, but most should be able to carry to mid-high silver.
Dont go ranked right at level 30. Pick 2 roles, and play tons of games at level 30 as them, with at least 2 champs per role (or do like i do and pick 1 champ who can go multiple roles and is rarely banned with 1 backup champ)
If you try and master all roles you will likely only be mediocre in all roles, and thus less likely to be able to carry to your rank. Remember even LCS teams specialize their players.
If you specialize in 1 role then you will be at a loss when you cant get it, which isnt actually common if you have good communication with your team in pre match lobby. A typical message i send at the begining of select would go something like this:
Me) Mid pref, top second pref
Me) I can support if i need to but im worse, and i cant adc or jungle
If someone else is above me in pick and wants the role i want ill say something like
Me) Its your call, i will support if i have to but we have a much better chance of winning if i dont.
Communication is key. Most players are willing to compromise as everyone wants to improve their rank. You must also be willing to compromise. Also, mention some bans you like to see as captains will often take at least 1 request if they see them.
Even so, having a backup role that youre still strong at means you have twice the chance of getting one youre good at. Even at last pick, its common for me to get mid or top.
Lastly, make sure youre at least adequate at support. Its the most common last pick role without communication, so its important you know how to do it decently enough in case you get stuck with it. If you plan on maining support then thats great and you can ignore this.
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