I just started back watching this over the weekend (didnt make it through the first episode last time i tried). Two episodes down, i'm mildly intrigued. It's giving me Breaking Bad vibes. And yeah Ruth is an interesting character.
Are you currently on season 4, episode 2 ... or season 1? I gather season 1.
I think what works for Ruth's character is that she isn't a physical presence, but she's foul-mouthed and volatile. But also vulnerable.