Trying to wrap my head around S&S subgenre conventions. Could I get some opinions?

Hey all! I am a 23 year old who grew up on high fantasy/epic fantasy/dark fantasy, ala The Lord of the Rings. Much of my relationship with fantasy to date has been through the lens of elves and orcs and wizards and "saving the world" (though I tend to prefer edgier stuff these days).

Sword & Sorcery is very new to me. I did not grow up with Conan or Red Sonja or anyone like that, so I'm stepping into it for the first time.

In the last year I have red A Princess of Mars and Tarnsman of Gor. (Yes, I think technically some might call these "Sword and Planet", but I digress.) I've also perused a few short stories and flash fics I've found online that label themselves as S&S.

I'm revisiting it now because at 3 AM the other night I got out of bed to write down some ideas I had for a novella-length story. I've never tried it before but I want to write S&S pulp fantasy, though I feel a little unprepared/uneducated on what is expected in the subgenre.

(Yes, I know that trying to conform to genre norms is often unproductive. I'm just writing this post for fun because I love tradition and want to learn more about this literary space.)

Okay, questions:

Is magic generally considered inherently evil/bad? In epic heroic fantasy, it's fairly typical for at least one of the party members to have magic powers that they learned through study or were born with. But I'm getting the impression that in S&S, the "sorcery" side of it is generally evil. Wicked mages in their towers trying to summon an evil god by butchering the princess on their altar, et cetera. Would it be unusual for protagonists to cast spells or wield magic items?

Where does the institution of slavery stand? My impression is that classic S&S protagonists spend a lot of their energy freeing slaves, which is noble. But I sort of figured that the whole draw of this subgenre is self-interested protagonists trying to survive and thrive in a brutal world. In the Roman sense, it seems perfectly reasonable in-universe that an established barbarian/warlord, even if he's the "good guy", would own some slaves if it's a semi-normal thing in the world. Someone has to look after the castle while he's away! Obviously no author should be endorsing the enslaving of humans, but I find the archetype of slaves/freed slaves to be very interesting texture for character ideas. But would it be against S&S norms for protagonists to own slaves?

What is the status of 'Civilisation'? In the fantasy I'm more familiar with, there are nations and kingdoms and such (though they're usually built on the bones of long-dead empires). But from what I have seen in S&S, those types of complex polities don't exist. The world seems to be organised around city-states, which is very cool. But that makes me wonder— is it acceptable for a few fledgling empires to exist in the world? What about the villages and towns and such? Like, who grows the food, and who protects/taxes the people who grow the food? Surely if I just started a farmstead or village or tribe out in the plains we'd be immediately ripped to shreds by roaming barbarians or monsters?

I am sure I have other questions. I am keen to hear your thoughts on these matters (and others). Also if you have any further reading for me, either S&S books or nonfiction essays commenting on the genre, I would love to hear them!