I’m an anarchist, but not well versed on theory (yet), so take what I say with a grain of salt.

there appear to be various instances where there is bo common answer [on how things should function], even within anarchist circles

Anarchism is a large group of similar ideas, randing from individualists, to collectivists/communists, to egoists, to syndicalists, to nihilists, and more. Ancaps are not anarchists, however (you cannot oppose all unjust hierarchies while deep-throating a capitalist’s boot). Anarchist movements are based on core ideals about hierarchy, the state, power, and anti-capitalism, there is a large diversity of thought within it.

Anarchists in the circles I’m in usually in propose using federations based on consensus-based direct democracy, and creating bottom-up horizontal structures, and using delegation to organize on a larger scale, such as “state-wide” regional, “national” or global. Note that when I say “state-wide” or “national” there will be no nations or states under anarchism, but I’m moreso loosely talking about geographic and demographic scales.

Some past societies include: CNT/FAI, Ukrainian Free Territories, and KPA Manchuria. Some current ones include Rojava and the Zapatistas.

Graeber and Wengrow go into detail about some anarchist-like societes that existed in the americas before they were genocided by colonists in their book “The Dawn of Everything”, which is the only book I’ve (partially) read on the topic at the moment.

There are tiny regions/communes that practice anarchist ideas, at a small scale within capitalist states. Jackson Rising, community responses to Hurricane Katrina, Stop Cop City/forest defender encampments, and the paris commune had/have anarchist principles at their core.

How does healthcare look under anarchism, especially on an industrial scale?

I’ve not read theory on this, but I know Margaret Killjoy talks about this in her podcast "Live Like the World is Dying", though I haven't listened to the episode

Although I haven't read theory on it, I'd assume the general argument relies on the fact that there are plenty of people who understand how drugs are manufactured, and how those supply chains work, and plenty of others capable of designing new supply chains. Through delegation and federation, knowledgable delegates can work with other federations to organize the supply chains to manufacture and distribute the medication. If a component is lacking, people would need to organize within their federation, or with other communities to get it done, rather than having a state give the directive to do XYZ to fix the problem.

are there any reading materials on concrete ways on how anarchist societies could function in modern times?

Zoe Baker and Anark are both authors/youtubers who have videos on anarchist organization, and both have extensive reading lists with old and new books on organization among many other topics. A lot of those books can be found for free on the anarchist library in various formats :)

I wish I could give a better explanation and more examples, but my ADHD brainworms get mad at me when I read, watch video essays or listen to podcasts.

Sorry for not linking, I’m on my phone