If you’re looking for an actual exploration of these kinds of questions, and if you’re ok with reading fiction, then The Dispossessed is a good one.

Some broad strokes:

There is this pair of moons that orbit each other, Anarres and Urras

• Anarres is anarchist, Urras is archist (complete with capitalist state, socialist state, and proxy wars)
• Anarres was set up at the request of revolutionaries on Urras, as a deal. The deal being “quit protesting and fuck off to the moon”

Anarres:

• All labor is coordinated by syndicates, and by request/consent. You will be sent requests from the syndicates asking for your labor in various ways. You have the option to disregard it, choose something else, or make your own work. Though if you just do nothing to contribute and always consume, you will be socially pressured to stop that and looked down upon.
• Their culture makes a big stink about owning any kind of property. Have you kept an orange blanket you’ve been fond of for years and years? That’s propertarian of you! (derogatory term)
• Everyone is treated as being a cell within an organism, a social organism. Everyone is shared by everyone. It’s basically a big hippie commune.
• The language on Anarres is a constructed language, focused on not having any kind of possessive language
• People still specialize their labor, but people in specialized fields will still be requested to join for general labor like farming, cooking, cleaning, etc
• Cafeterias are public, everyone sleeps in dormitories, few people live in a room to themselves

So I’m gonna answer the more-specifi/remaining questions as in universe:

In a place without the state, how can we ensure the state remains without governance?

For Anarres, it remains without a state because it’s a pretty barren moon. Getting to it is hard, and once you get there, there isn’t a whole lot. Anarres does trade some metals and supplies with Urras though. So between it just not being of much use, Urras already getting what they want (they see Anarres as a mining colony), and the prohibitive logistics of waging war across space, it just doesn’t make sense.

Wreckless revolutionaries?

Yes and no. The people of Anarres loosely see themselves as revolutionaries, because it’s a persistent thing, the cornerstone of their society. It’s also something that continually needs addressed, because they do have some bureaucracy despite their lack of state. The job postings they get recommended for instance, are recommended through computers in a centralized place (they’re trying to decentralize it as best they can).

But on the other hand, they’re not actively fighting against a bourgeoisie class, because there are no classes on their moon.

In a place without the state, how can we ensure the state remains without governance?

Thats one of the problems Anarres has, they’re in some ways slipping into governance. For instance the protagonist of the book has his scientific work hindered by the fact that he has other scientists that do not see the value of his work, so they do not aid to publish his work. It becomes a bureaucracy of social force.

Even with power, can one be truly responsible to hold it? Even if collectively?

On Anarres, the social force of your peers tends to keep that in check. They mention that they used to have public roastings of people who failed or otherwise kept too much power. But not the fun kind of joking roast, but actually ruthless and meant to demean.

What is the ideal Anarchist stance on life and how it could be lived (not should)? Is it true to the definition of Anarchy? Every person for themselves, or each person for one another?

Every person for one another. Everyone belongs to everyone else in the social organism, no one person can ever own another. Not through family, religion, job posting, or language.

Anyways, it’s a damn good book, and I highly recommend reading it if you find political theory books boring like I do.