Aluminum cans have a plastic lining.

But all of that plastic is incinerated and even otherwise hopefully less prone to micro plastic production, so not a real issue?

IFF recycled.

I don't believe it is so straight forward. Aluminium smeltering is an extremely CO2 intensive process (essentially you need a lot of natural gas to generate the heat, I think there are experiments with hydrogen but they are nowhere ready yet). Moreover in contrast to glass recycling where you can reuse the bottle (common in many areas), that's not possible with aluminium. The big advantage is weight, so a comparison between glass and aluminium typically depends a lot on transportation distances and how complex recycling processes are.

I think Iceland has a big (big for Iceland, at least) aluminium smelting industry. They don't have the ore, but plenty of cheap hydro and geothermal energy.

Aluminium melts at temperatures that, as far as ovens are concerned, can be classified as "tame". Sure, the oven needs to be built heat-resistant, but a melting point of just 660C allows things like uncooled structural steel to be used. This is so tame, that the molten salt type nuclear reactors (well, some of them) are able to serve as a heat source for such an aluminium recycling oven. 10 years ago there were coal power plants in active development that used high-pressure (around 350 atmospheres; 75% higher than what consumer-grade pressure washers tend to max out at) supercritical (700C) water to drive the first stage of their turbines, in an effort to extract more of the coal's chemical energy through exploiting a greater temperature drop. The aluminium oven does not need to handle such severe pressures, or contact with fast-flowing liquid that is as corrosive as water at those conditions (they can use a gas between the heat source and the aluminium, and fire brick style material between the aluminium and the structural walls of the molten-aluminium-bucket).

The heat is typically electric (which may or may not be CO2 intensive).

The reaction does produce CO2.

Totally agree aluminum is well recycled and glass hits even higher percentages outside the USA.

* * *