Not sure I'm fully answering your question here but I think the show is ultimately about forgiveness, redemption, and the weight of family trauma/obligations. It's mostly tied into the drug/robbery plot but that thread pops up for all the characters imo.
Ruffalo is good in it - but I think Tom Pelphrey (the other lead) was phenomenal and the rest of Ruffalo's crew shines in the back half of the season. Honestly for me Pelphrey's character was worth the watch alone. Ruffalo's arc is somewhat disconnected (not in a bad way, just separate) from the drug/robbery plot line.
I thought it took 2 episodes to come together so if at the end of that you're still not into the series, it's probably not worth continuing on.