Wasn't that - and the scenes from Discovery - reportedly added in post without the knowledge of the directors?
Not exactly. So the story goes, the "funhouse turbolift" was thought up by Kurtzman for the episode Brother, season 2 premiere which he himself did direct. The issue was, he basically decreed this through executive fiat on account of he's the guy currently in charge of the franchise without consulting at all with the show's art department, who had already come up with their own internal layout of the ship which did not take into account a massive roller coaster in the middle.
Supposedly, this was one of Kurtzman's various "canon fixing" initiatives for Disco's second season in which he felt the need to explain why the Crossfield class is double the size of a Constitution class, but only a fraction of the crew (130 for the Crossfield class, 400 for the Constitution class). So his solution was that on the Crossfield class, all the habitable areas are on the ship's perimeter, with the rest of the ship being a giant hollow space in which the rollercoaster turbolift is housed.
Then they went and completely disregarded this in the Q&A Short Trek showing the Constitution class also has a rollercoaster turbolift.
The early TNG civilian clothing.
Civilian clothes in all TNG is pretty bad. Or really, in any 24th century show. Except Picard.
Unless there are massive numbers of enlisted that we just don't see, most of the "basic" work is carried out by officers - which is also backed up in canon. Starfleet, as portrayed, is mostly super-educated and super-capable officers doing most things. For everything else there should be automated processes and robots.
Well, no. We do know there are enlisted personnel who do the menial stuff. Voyager Good Shepherd for example, you had Mortimer Herron, a guy who spent his days doing really basic stuff on the ship's lowest deck. And according to that episode, he was intentionally doing stuff he was overqualified to do, B'Ellanna claimed she's tried getting him to do more heavy lifting, which he had always refused.
If there are actually large numbers of enlisted, as would be logical following current naval tradition, that would only make it more likely the young officers we are following should be elite.
Except not everyone can be "elite." There's a saying where I work "someone's got to be the worst." There's always going to be someone who is a weak link. That does not necessarily mean they're completely incompetent, it just means they are not a shining star making waves everywhere they go. For some people, being in Starfleet is just a job. A good majority of Starfleet personnel we see seem to be career officers, they join Starfleet with the intent of someday making Admiral or something. Really, the junior officer ranks should be filled with people who have career ambitions outside of Starfleet, and are just serving in Starfleet as a stepping stone towards whatever it is they want to move onto next in their life. The idea that everyone who becomes an officer wants to someday become a Captain or Admiral just isn't realistic.
Besides, if Starfleet officers are the Federation's pinnacle of perfection, and they attain higher rank as representation of how they are the best of the best of the best, then it paints a pretty bad picture that so many evil people become Starfleet Admirals.
That means the apocalypse is right around the corner!
Meh, welcome to 2020.