I have issues with movies or TV series that feature only unlikable characters. I never gave Succession much of a change and maybe I don't qualify to give it a rating after watching just the first couple of episodes1. It didn't make me want to continue watching. I give it a benevolent 2 stars. And I think Kieran Culkin is a good actor.
If you like watching rich assholes being themselves, then give it a go! I didn't like House of Cards for the same reason and was right about Kevin Spacey being a horrible person in real life. Interestingly, the one person who recommended the show to me most, ended up being a real douche nozzle and just all around crappy person. Quite telling. I'm not saying that everyone that likes this show is an asshole. It's just that I've been dealing with too many assholes, including aforementioned ex-coworker, I don't need to spend my leisure time watching more assholes do their thing.
1 but this is my website so I can do what I want