Sicilian Dragon Yugoslav: Rook Sac(Exchange sac) and Bishop Sac

I play Sicilian as Black.

I know that there is a Rxc3 in this variation of Sicilian Dragon and there is also Bxg4 when white plays g4 and then black plays Nxe4, opening the diagonal of the g7 bishop. I don't know when to play it.

I tried it while playing blitz but didn't get mating attacks.

What are the conditions i must keep in mind while doing these sacs? (Sicilian Experts, please help)

When Black plays Rxc3, why don't white play Qxc3? In all the games I played, they play bxc3.

Thanks for your valuable time Sir.

What if black plays g4 to prepare h5 and attack with moves like Bh6, hxg6 Bxg7 Qh6+

If you play the dragon against people who know their theory, and are likely to win the game while completely still in theory, then you should learn it too. If you play it against people who "just play normally" then you'll be okay as you are.

Thank you