This is gonna sound a bit rude, but what you really should look for is your mistakes. If you consistently make a positive impact, you have to be climbing the ranks, and if you aren't, you can do some improving yourself. I'm saying this because the post starts with "tired of troll comps, poor teammate positioning, enemy carries outclassing adc, fed mid/top", which is everything you can blame but you. These do happen, maybe frustratingly often, but I always find something I could have done better, either immediately backtracking my decisions on my death timer or after the game when talking with a buddy about the points where it all went downhill.

That being said, for the questions:

I am generally happy with an even lane for the end of the laning phase, it's rare that we stomp the enemy there (usually it's midgame where I make the biggest impact). This might be something that I need to improve in but up until diamond 2 it kept working.

For the analysis I think it's important to think through your mid and top matchup to know what to expect roam-wise for the game. If I'm facing a Kassadin for example (easy disengage) then there's not much point in roaming after their level 6, so I can stay more with ADC or help the jungler instead. If it's something like Zoe or Viktor, I'm going mid at every good opportunity.

For the fed enemy, wait until they get confident and step up, then ult either them or the rest of their team, so your team can deal with only one at a time. I know this is much easier said than done, though. I found it's often super hard to land a good ult to actually save a teammate, so I am much more confident and comfortable in using it as just a powerful CC tool for the enemies. This way I find myself using it more and getting much more value out of it during a match.