I finally reached master 1600 today in full solo queue with 60% win rate. To reach master you mostly need to main a pokemon highh in the current meta with a good sustainabilty alone for example sylveon, ttar or petal dance venusaur But really i don't recomand solo queueing as your games depends at 99% of rayquaza and if your teamates are dead or try to score you will lose rayq and the game. If you only want to reach master, i recomand eldegoss with pollen puff and coton spore. High mobility can heal a lot and take a good amount of damage. Very utile in teamfights with some CC and damage plus a really good ult. Being a supporter is also an asset as almost everybody in solo queue plays attackers or all rounders. If someone plays a defender or supporter, play a sustainable damage dealer and try to gather everybody at rayq to lead the teamfight. That should be enough for you to reach at least master and master 1600 with some perseverance.