I did t say it was darker, I said it was more grimdark
(Though I had also temporarily forgotten Alien 3. That happens)
Neither Discovery or Picard could truly be classified as "grimdark." Neither take place in a dystopic setting which is a defining feature. In fact, just the opposite, you have relatively dark things happening in a utopian setting and it is that disharmony that creates the drama and suspense while the bleak, violent and disturbing subject matter in a "grimdark" work is actually harmonious.
grimdark
[ˈɡrimˌdärk]
NOUN
ADJECTIVE
- a genre of fiction, especially fantasy fiction, characterized by disturbing, violent, or bleak subject matter and a dystopian setting.
"I was super into grimdark when I was in college"
- (of fiction, especially fantasy fiction) characterized by disturbing, violent, or bleak subject matter and a dystopian setting.
"there were two series that were too grimdark for me"