Game play is obviously a lot more complicated than just looking at your KDA, items, and creep score. On the face of it, it kind of looks like you have all of that down pat. When you play Support, you look like you're getting Assists so it seems like you're participating in team fights and hopefully roaming to provide help where needed. When you play other lanes, it looks like you're good at last hitting and farming.
Where it looks to me like your team might be missing the mark is completing objectives and pushing. For example, I didn't see **any ** Baron kills on any of your screenshots. There are dragon kills but they don't seem to be consistent. I also suspect that pushing and killing Towers is a problem because it doesn't appear as though your teams are getting to the inhibs and then flopping. Most of the games that you've listed here have few towers and inhibs taken by your team. So, it seems like the teams you are playing on aren't pushing hard enough.
I really can't tell if your team is doing a good job with Warding but that's something that usually needs work. Everyone on your team should be warding. It is NOT just the Support's responsibility. If you see a player that isn't using Wards, you should ask them to drop some.
You could probably work on reducing your number of deaths. You might be over extending, over staying, making bad decisions (ie, chasing when you shouldn't) or again - lack of visibility could be contributing. Fewer deaths = less gold for the enemy team.
Lastly, one way to improve is to try and have only 1-2 picks per lane that you consistently choose. Another is to go watch eSports, videos of streamers and gamers that play Ranked games, and read through people's build guides for the Champions you like to play.
I'd say that you can probably improve in a lot of areas. I know that I still have a long way to go to be a better player.
