Some cases its not how many hours you put into something but what you put into those hours. I could play League for 10 hours straight and if I don't learn from my mistakes I'm wasting my time and others.
Also depends this game is fun but rewarding its hit and miss.
Hit if you can get to Diamond and seem like your not boosted you can get start a stream and people will watch you play but you can't play like you got boosted.
Miss as this game can be addictive and if you don't go far you pretty much wasted whatever amount of time that you put into playing it.
Say you do reach challenger at that point it will be hard for you to stay up with REAL LIFE SITUATIONS. If you want to stay in challenger you will need to play almost 24/7 and practice equally as much. This means that it will be hard for a job or Real life situations for you.
Whenever you have a chance to play without being interrupted I would sit down and play Ranked. Whatever role you play have a positive KDA and play one game after the other, play say .... 20 Games in a ROW no breaks other than bathroom break or breaks loading into the game.
IF you don't WIN 14 or more out of the 20 games while having a positive KDA, the Challenger scene may not be for you.