General Discussionwinrate, skill bracket, and mmr

is there a relation between skill brackets win rate, and mmr
if yes i have 56.60% winrate , but still in normal skill, i had like 10 matchs win in raw recently (even with bad kda)
but stucks in nsb, and for that reason i dont wanna start ranked matches,

and beside win rate what can i do to reach at least high skill bracket (very high I'll see one by one )

ps: maybe the reason why is im bad at farming (xpm , gpm)

help thank you