Yes, I think that's one of this game's biggest strengths; it allows for a broad spectrum of player actions, and actually shapes the narrative (to a degree) around those actions. I do think there ought to be a way to avoid the >!boss fight at the end of Act 2,!< but overall the freedom you have is really impressive. I'm in Act 3 of my first playthrough (total dark urge murderhobo) and I'm constantly impressed both by the scope and depth of the bad guy route, as well as the sheer amount of content I'm completely missing by telling lost kids to kick rocks, and casually slaughtering dozens of fully-voiced, potentially quest-giving NPC's. It's a glorious game. Definitely in the top 5 of the last decade, along with Witcher 3 and Disco Elysium.

I was shocked when I found out astarion was a party character. I told him to take a hike because he just tried to kill me. Haven't heard a thing from him. It just let me do that.

You can kill basically anyone, and the game just goes on fine. You face consequences for that, but you aren't railroaded at all.