Promos feel SO bad

There's no reason as to why I keep hitting my plat promos only to either lose them every time due to a 3 game loss streak or immediately demote from a 3game loss streak. It feels like way too much of an uphill battle. I hate to sound like "that guy," but at a certain point, it feels bad having teammates who constantly just don't bring anything good to the table.

I'll admit not all of my games are stellar, but more often than not I win lane or at least go even only for the 20 min mark to hit when laning phase starts to end and I realize my whole team is behind on objectives and mostly everyone on my team has negative KDA.

I just don't get how it makes sense that I get win streaks to either get back into promos or hit plat1 again, only to be hit with another loss streak directly after.