I want to Improve as a Support Main

So over the past 3 years I have climbed from Bronze 5 to Plat 4. I have drifted from role to role but always ended up back at support. There is a lot of material out there for climbing out of gold and under but not a lot of information for climbing from Plat and above. As a Support main I would like to know what is the role of a support in mid/higher elo? What do Higher Elo players look for in a support? And What are the best ways to imfluence a game as a support in higher elo?

Thank you and good luck on the RIft Lavender