Plat is going to be the death of me

Past 4 days, I hop on, I lose 80 percent of my games, after every 2nd loss I take a break, reavaluate and hop back on. Then suddenly, I start winning and winning and make it to plat 1. I will Then get off for the night and reheat the next day.

Feel like im in hell. I play venom, groot, invisible woman or jeff so I can always play someone usefull no matter the team comp, I always use my mic and give coms on Who's dead and when উম ulting, I feel like im doing my job, but I just feel like I cant win and get into diamond so I can get rid of wolverine and luna. I never blame my teamates (unless ive kindly asked them to please switch when They're not doing great and then they hit me with a "10k damage" as if They're not playing punisher) and I will always try to help my supports if They're getting dived when I play tank.

What more can I really be doing?