The two have very different content. Hikaru is mostly live blitz play with commentary by one of the best in the world (possibly the best for the formats he play

The two have very different content. Hikaru is mostly live blitz play with commentary by one of the best in the world (possibly the best for the formats he plays) while Agadmator is only analysis of typically classical games by an otherwise weaker player. As for me, I prefer neither and like more educational content that doesn't focus on games at the very top (e.g. Naroditsky's or chessbrah's speedruns) but that doesn't change that Hikaru is more popular than them or Agadmator.