Could someone explain the food replicator? I thought they weren’t invented yet? Or were they showing an early beta version that can’t get anything right?

That was a "food synthesizer", a precursor to the TNG era replicator which is more limited in capabilities.

I'm not a vet and I don't have PTSD but my girlfriend and I had some pretty similar issues to you with this episode. I think, thankfully, the episode doesn't seem to expect us to think that M'benga was "right" at the end, or to be happy about what happened, and the final scene between him and Pike is critically important because I don't think Pike is supposed to look foolish in that scene. Absent that, this episode would feel really gross to me.

As it is, really the only way I can work with this is knowing that the actual arc here is the enormous one that concludes with Star Trek VI, a movie that I feel only gets more radical with every year that passes and every rewatch I give it. Kirk's realization that he has to let go of all the pain and anger in that movie and allow the world to move on and healing to begin is, when you get down to it, maybe the most optimistic and important message the franchise has ever really tried to express, and if this episode exists as a "middle chapter" between the war itself and that eventual endpoint...well...I can work with it as that middle chapter. But I still feel pretty crummy about it.

I understand your reaction.

For me, this is in many ways a less dark and cynical take than DS9 In the Pale Moonlight and certainly the Section 31 references.

What was critical here was the difference between the journey of individual traumatized officers who had been forced repeatedly to take actions in wartime that compromised their values, and brought out capabilities they never sought to own, vs Starfleet leadership taking cynical action. It’s also a direct outcome of Starfleet’s cynical actions in having M’Benga develop the serum and then use it.

Starfleet’s postwar directive, and Pike’s insistence on pressing it with his senior officers, created the immediate crisis.

However, we need to take account of the fact that it was the ambassador’s own repeated insistence on confronting, engaging and attempting to recruit M’Benga to assist in his mission that led to the break.

M’Benga seemed to be processing his trauma and managing it as well as he could. He wasn’t at the point of exposing the ambassador’s deceit although he appeared to have been contemplating it.

It was the ambassador’s decision to seek M’Benga out again, in his own safe space, his private office, and own refusal to take M’Benga’s rejection that seemed to take the contemplation to action.

The cover up by Chapel and M’Benga is serious, and in the case of M’Benga this is the second case of his hiding something of significance from his captain. He’s an understandable but grey character, and we will have to see where the show takes him.

In Chapel’s case, we have been shown that her bright effervescence hides much darker experiences. It’s now easier to imagine how she will evolves to the very restrained version of herself in TOS.

I feel this is a very authentic portrayal of the chronic legacy unaddressed of trauma in individuals, how a military service and society will need to move on after a society-wide war when its individuals are not yet ready to do so, and how disasterous the potential outcomes when the divide been societal and individual needs in healing are ignored.

It’s not the 24th century Starfleet we’re seeing where there has been a long period of peace and officers can be treated effectively for trauma before returning to duty and it locks in with chronic effects.

I agree that it does not show Pike’s leadership in a positive light, but I find it realistic. What it does show is the gulf between war veterans and those senior officers who, while veterans of other kinds of conflicts, were not involved.

Starfleet needs senior officers, without direct personal history, like Pike to lead the peace and move forward, just as the western allies needed to find a way with some German leaders and scientists after WW2. But not every individual at the front can withstand the stress of that direct engagement with a former enemy.

Starfleet’s order to force veterans into direct contact with a former enemy was psychologically unhealthy and unrealistic, but a value-focused officer like Pike would not have the insight to see that.

This gulf was underscored at a personal level by Chapel’s conversation with Spock, when she could not share her experience with him and he could not ease her pain. The scene between them was an essential confirmation.

What I found interesting is that Number One had the best read on the situation. She saw the pressure the ambassador was putting directly on the veterans in the crew.

As the executive officer, it’s her job to manage personnel, to assess readiness, to deliver a functioning ship for the captain’s command. She accurately saw the problem and recommended action to mitigate the situation by reducing the time to deliver the ambassador to Starbase 24.

What she was not able to do however was to convince Pike to stand down a bit on Starfleet’s toxic order to require veterans of the war to show acceptance of the ambassador. Nor did we see her attempt to try to convince Pike. He was leading from his values and unable to really take measure of its impact on the individuals.

I find it interesting that this show is giving us episodes that show the negatives of Pike’s command style as well as the strengths. While we’ve seen the negatives in Kirk’s and Picard’s temperament’s and command styles acknowledged in the movies and in Picard, this seems to be the first time we’ve had it done with a hero captain in an ongoing television series when he’s in active command of the ship.

I don't think it's been identified. However, she is a long-serving Starfleet officer, and was both a Chief Fleet Inspector and a (probably senior) instructor at Starfleet Academy before joining the Enterprise, so you could make a reasonable guess that it's a badge of seniority/advanced qualification.