Need Help!!! Someone high Elo adopt me

Hey guys..... alright so I need some help... I’ve been playing league heavily the last year or so and have been lurking around S5-S4 for the last month or so. I got to S4 being an adc main but started playing other roles.. throughout all the roles I have like a 47% win rate now.. I know the majority of the game and watch a bunch of esports and other videos to learn. I need help fully understanding how to count and be accurate for wave manipulation and other things (any tips?). I have a hard time understanding these matchups, like I know a Morgana is good against a blitz or thresh for her shield etc but what about everyone else? How do the pros know who’s better than someone else, I’ve read the abilities in the game and I swear sometimes it feels like there’s things a player can get a champion to do that isn’t written.. lastly I need help with itemization. I know to build grievous wounds as an adc if there is a lot of health regen on their team or stuff like that, but how else should I be building based on comps? Typically it seems like the builds are pretty similar but then you’ll see pros throw in different stuff, I just wanna know how I know or tips to be better than my opponent. OH and one last question would be how do you track your eyes? Like do you watch the game then go mini map or how do the pros pick up on little stuff like that on the map.

Edit: lol sorry guys I actually thought of two more things. Despite the roll you play, where and when should vision be placed? I’ve watched videos about keeping vision in a “line” from tower to tower through the jungle, creating a “vision wall” but what if you’re ahead and wanna play wards deep? Best spots to place them? Do you play around the objectives and ward around them? & then now lastly, how can I improve on farm? I have never hit 100 cs at 10 or even gone even. Pros are sometime 250 at like 22 minutes and it makes me wonder how the hell they do it?? I know it goes to wave manipulation and everything but are they also killing jungle camps? When do they go? How can i use wave management to get better cs? I’m confused on slow and fast pushes if I kill the melee minions or just kill the casters and leave the melees for my minions to kill (but then I miss cs)... I think you all can see how I’m confused on this stuff haha it’s becoming very tilting so I decided it was time To come to the boards and ask for help.

Really just looking for all the macro tips you can give me. Much love for all the help you guys!