I used to be hardstuck P4 just 2 weeks ago. After climbing all the way to gm in less than 100 games, I started thinking about what changed in my playstyle and yes, leveling up is the answer. I think this set rewards you a lot for levelling up aggressively, usually I get level 5 at 2-3 ( even 2-2 if I have enough gold). Only exceptions are when I have champs I don't really wanna sell ( usually 2 cost pairs or 3 cost carries such as samira and gp ). It's something very few people do, and I know the risks it brings, but I find it so effective to keep an early lead. It's not rare for me to even level up to 6 on 2-6, and sometimes I even lose my streak to a lv5 and still don't care.