Best response to advanced caro kann?

I always play c5, although the engine says Bf5 is better. I don't like the position when opponent played g4 instead of Nf3. Im thinking what to play after g4?

If you're going to play 3. ..Bf5, beware of the Tal Variation (4. h4), where you must play 4. ..h5! or else you lose immediately. Even after that, you're going to have trouble developing on the kingside.

The Caro-Kann Advance Variation is, in my view, best handled like a delayed French Defense, so as hard as this might be to accept, 3. ..e6 is a sensible third move, intending c5 later. Study the Caro-Kann games of Tigran Petrosian, who generally avoided 3. ..Bf5, either leaving that bishop on its starting square, or waiting for white to play a Nf3, responding with Bg4 with the intention of exchanging on f3.

Against 4.h4, 4...h5 is not a must. 4...h6 is possible, or even other moves work too. Just DO NOT play 4...e6, then your Bishop is trapped. But there are lines where you do not play e6, and if g4, the Bishop goes back to d7.

That said, got better advice for the OP on move 1. Move the e-pawn instead. How far doesn't matter, just move that e-pawn against 1.e4.