I doubt it's just with Spock. It might be a factor but not the whole story.
Humans are complicated. One event is not causal.
I think it is a major part of the story, something went bad with spock that made chapel as she is in tos. It also means even when she gets engaged to korby, she is still in love with spock.
Now when it comes to uhura's been younger. I wonder if this was a
conscious decision by the writers because they thought making her younger will not make people think much of the saldana version even if 99% of trek fans already know saldana version in an alternate uhura.
To be real, in mainstream media uhura is perhaps the best known female character to be a love interest to spock thanks to the kelvin films. she is also the only female character that is part of the core 7 in TOS .
the first JJ film in 2009 was very very successful and made star trek popular even in a way tos never did in its prime. the kelvin cast are still more known in media and pop culture than snw cast ever will be.
In fact i am curious about snw ratings because paramount once said, the show was their most watched trek show since Prodigy that got cancelled and paramount gives away free episodes on snw on youtube. this can only mean the ratings are very low. lower than discovery that no one talked about in mainstream media after season 1.
SNW is popular with many old school trek fans but has not seen major mainstream success like TNG did or TOS became later in pop culture or the first Kelvin movie.
i do wonder part of the reason why we got an uhura you are
all trying to point is much much younger that feels like a big deal. the showrunners were worried that if they had cast an ''older uhura'', some who are aware of the kelvin films will wonder why she is not spock's interest here, so making her much younger was a way to make sure uhura does not derail any of the angles of the spock/chapel/trping love triangle.
Not to mention in TOS, while spock is mostly paired with kirk as a lover by fans. uhura was more favoured as a female partner to pair spock with than chapel they found boring or tpring they found to be a cruel person. Although I do credit a lot of this to people having so much love for nichelle nichols and uhura been one of the few black female characters on tv that broke grounds in portraying black women in a great light apart from the usual maid roles. This is who SNW Uhura will still become.
I think Uhura by star trek lore going into this show was obviously more established and more well known than both Chapel and Tpring and the creators of the show felt they had no choice but to make her younger than everyone else, so people don't see her as a love interest to spock or even kirk. which should be creepy to some since kirk is kind of dating khan decedent based on the creepy logic of youngness.
However none of this matters as long as they keep saying SNW is prime star trek. these actors are going to start acting like their tos self soon. SNW uhura will become what nichelle tos uhura became and snw chapel will become with tos chapel became, same goes for Peck's Spock.
the only character I truly feel sorry for is Pike because he is aware of what is to come.
hypothetically*, someone could watch the movie Titanic, knowing that the ship will sink in the end, but still want to enjoy the story of Jack and Rose.
*And yes, sadly I know too well, that not everyone who watched Titanic was aware of the fact that that ship sank, or was even real
ehh..this is not a great example to what is discussed because as you said, we know the ship sinks. that fate of the ship is sealed. some here are trying to ignore the fate of snw characters by pretending
1. uhura is meant to be younger than everyone else. (not true)
2. Spock is still meant to care deeply about chapel and tpring
(not true)
3. SNW is not a direct prequel to TOS
(not true)
4. the titanic sinks
(true)