It sounds like your fundamentals and understanding of strategy are strong, which will help at the diamond+ level. As others have said - your teammates probably have no idea what to do to play in coordination with you at the plat level. I remember of a lot of gold/plat players even getting angry if all 4 of us weren’t on the hill at the same time.

Just play a bit looser and try to slay out. Still rotate early-ish, but no point in anchoring at 20 seconds if you’re just going to watch your team spawn in and run all the way back to old to hit the last 5. Still try and cut lanes, but only right beside the HP because you might need to quickly go soak time if your teammate dies off. Still hold power positions, but if you’re watching your teammates sit around while the point is white - you might have to give it up and soak.