Game of Thrones is way more nihilist than Rick and Morty or Seinfeld. At least when it comes to morality, ethics, and humanity in general.

Rick and Seinfeld do some scummy things out of pure self interest (or disinterest), but Game of Thrones is 100% about taking the training wheels off and letting characters rape and murder each other. Rick doesn't take slaves. Jerry doesn't have his rivals killed.

What's more, fans of Game of Thrones often root against the non-nihilist characters for not being "smarter". "Dumb" characters are often guilty of loyalty or romance or honor.

I say this as someone who enjoys the show. But I enjoy it as a thought experiment of a different society with different rules and culture.