My friend invited me to this poker game and I'm trying to figure out if I should continue playing. Here are the facts:

Pros:
-lots of fish (I live in South Korea where poker knowledge isn't all that developed. I.e in the 9-max game, about 3 to 4 are fish imo)

Cons:
-you must play for atleast 3 hours if you have a winning stack
-straddles are mandatory (meaning if one person chooses to straddle then everyone is forced to do a round of straddle which means the game feels more like 1/2/5/10)
-Because the game is more like 1/2/5/10, buying in for 500 (bc of my BR management) is actually playing short-stacked (which I dont like)
-rakes are high (10%)

Keep in mind I have only played one session here and I am mostly a casual player. If I did continue to play, what kind of preflop and postflop strategy would you recommend? Thanks!

Rake 10% capped at ???
If its capped at 5 then it sounds to me like a great game.

Is there no legal live poker in SK?

There is but the casino games are filled with tight regs with the occasional fish on weekends. And so I try and avoid those games.

Yes capped at 5

Bring me there.

It is impossible to tell if the game is profitable for you without knowing much more. As mentioned by others, the rake structure is excellent, so that is a positive sign. On the other hand, poker is illegal in South Korea outside of casinos. I don't know how well the law is enforced in this situation, but a raid where you were fined and lose your stack would make the game unprofitable.