I think it's best not to get too deep into what it is because the smaller it gets the weirder it is.

As you say ohms is the measurement of resistance. Everything gives some resistance but others give very little to the point we say it's non existent or not applicable. But there is "some" even if it's very very very very little of it. Basically zero.

Why is some conductive and others super conductive?

Lol, like I said electricity is stramge. Everything is held together by electricity. Then again, as scientist Nassim H. revealed to us, that there is only one electron in the entire universe, makes me wonder why the electricity? What is electricity anyways? An after effect of that one electron traveling everywhere at the same time? I don't know. Even top scientist are baffled by what it truly is.

What makes something conductive?

In electricity, it is the current or amount of electricity flowing through per second. When one says it's super conductive, it means that the ions in said material has a higher capacity to pass electrical current from one to another of similar resistance.

This may shed some more light to it, I find it to be accurate:
https://www.britannica.com/science/conductivity

Good thing we have webby. Plenty of information out there. And plenty of videos explaining it too. I even catch myself watching a few about such trivial things to the date.

My main focus at the moment is finding free energy mechanism that I can afford to build on my own. A Tesla coil seems fun to do but can be rather real dangerous if done incorrectly as it has probability of extreme high voltages. The most I have had flow through me 1200volts. That was major scare lol. It's not so bad but if it was amps i wouldn't be telling you all of this today.