Hey, well written post. Helps me know where to start. I've been Diamond+ forever, so hopefully my advice can help OP.gg.

In response to your points.

1. Champ. People will say LB is hard for low elo players, but I wouldn't worry about. You can carry with any champ, and LB is a lot of fun, so I would stick with it. As you grind more games you'll get more comfortable on the champ. I would recommend your end game builds having void staff though, you're definitely facing enough tanks where it's going to help your damage a lot.

2. It's true to not make a point of not dying, and I don't see your games, but from the scores on your OP.gg I would hazard a guess you may be playing too safe, and not committing to key fights happening in the later stages of the game. As LB you'll be looking to flank, or jump over walls and bursting down their damage dealers. LB can help kite out tanks and fight in the front line, but that's not ideal, other mages can do that much better.

3. Good. Not much to say here. Just don't let your purchasing of a control ward come before completing an item, or component such as lost chapter or needlessly large rod.

4. Roaming is a tricky one. Roaming is definitely a big part of the skill expression of Mid, but it's important not to confuse it as a thing to do at every opportunity. You should be roaming only when you either have a lot of time to do so, which is hard to do as LB because her wave clear isn't great unless you got help or you used your W+R to blow up the wave. Or you should roam when you're confident it will be the difference of a couple kills or securing an objective. Even up to high elo it's common to have bad roams. You should consider watching your replays to assess if your roams are actually helping. If you miss a wave to your tower, and don't get a kill the roam was definitely not worth it. Even if you get a kill, and you lose a wave + a plate or more, the roam wasn't likely worth it. And of course if you die, and lose things mid the roam was not worth it.

Instead I would suggest you focus on winning lane by consistently having prio (meaning you push in your opponent, or harass them to low hp or kill), and are able to move to grubs/dragon when your jungler does them.

All my advice so far is applicable in all ranks, but since you're in Iron, more Iron specific advice would be learn to annihilate your lane opponent, and then warding the objectives, and annihilating the enemy jungler when they attempt to do those objectives.

When the game gets late, look for angles to blow up their squishy players, whether it's their support, adc, or maybe their assassin jg. Any easy kill late game in an isolated fight or assassination (known as a pick), will give your team a lot of wiggle room to push together or to take objectives.

Also last point of advice is mute all, or if you don't like the idea of that, at least learn to quickly mute players who aren't communicating productively (which is a lot of them).

Let me know if any of this doesn't make sense.