See, the thing is... many people in lower elo ARE newer to the game. And new to ranked - not all - but many. So their entire experience doing some strat or playing some champ might be positive up to that point - they purely don't have the experience with all different matchups nor experience playing against a "good" opponent to know that maybe: the strategy isn't good or that they aren't as good as they thought.
If my bot goes 1/4/0 in a 2v2 - no ganks by enemy team, they're not doing so good. But if they are playing as safely as possible and not trying to fight when the enemy bot is fed, they are having a bad game. When they are shoving to enemy tower, fighting in river with no vision, and forcing engages on the fed enemy duo that they fed 2v2, they are inting. I tell them to just play safe and farm up. If they KEEP playing agro and forcing bad plays, then they get a report because they should know better at that point. First they should know because they know they lost 2v2 multiple times and the enemy only has an easier time winning now - since they have more levels and items. Secondly they should know because a teammate(s) told them. People these days just don't respect that someone else on the team MIGHT know better than them - especially when said people are having a bad game.
As for malphite support - it is a thing and it can be good. Most run stoneborn pact and rely on q in early levels. Malph q's someone and you aa them for free healing. Beyond that, you mostly look to hit 6, and hopefully you have a high burst adc - maybe with some cc too. Mf, jinx, trist, draven, and twitch are probably some of the best to pair with malphite.
And as for climbing... teammates don't really tend to get smarter - just better mechanically. They still force stupid 2v3's and 3v5's for no reason. They still go 1/6/0 in lane. They still fail to ward with their free trinket wards. It's a rare experience to get a team where you are all on a similar page about rotations, objective priorities, etc. and just dominate the map with better macro play. Most games it's still people showing up late to an objective. People not forcing a 5v3 around an objective when the enemy is split up. People rotating to save an outer tower that they won't be there in time to save instead of 5v4 forcing an inner tower in another lane.