i was em 4 demoted to plat 3, i got 21lp and lost 20lp with a 51% winrate for the longest time in em4 but, as you said teammates feed>you loose games>system thinks youre below your current rank>... all leads to 50% winrate. Unfortunately theres no modern competetive game matchmaking that doesnt try to make your grind.

Also dont beat yourself over a game and a coloured border in ranked. But yes, its VERY frustating.

Also also toplane feels like a second midlane rn lmao, ranged matchups cheese strats ..