how to go from L3 - masters

I push ranked solo and I can get to legendary 3 pretty easily. Inside legendary 3 I can win games and got to 8.8k as my peak but then I'll go on a huge losing streak and fall all the way down to legendary 1. This has happened multiple times this season and earlier seasons where I'll get to legendary 3 then tilt all the way to the beginning. I consistently get star player and try to not let bad randoms get to me but at this rate idk if i'll reach masters anytime soon, does anyone who's pushed masters solo have any tips? I started 3 months ago so I only have these brawlers to use
P11/hypercharge: Darryl, Melodie, Dynamike, Nita, Surge, Amber
p10: Gus, Kenji, Angelo, RT, L&L