Consider Natasha helping Steve break their friends out of the Raft, and seeing the way Wanda was restrained and treated like a weapon more than a human, after having just dealt with all this renewed Red Room trauma.
Gee, thanks, Satan.
I love that we have official canon confirmation that Nat was part of the Raft breakout (although, honestly, Civil War not making that clear from the get-go was a fucking PROBLEM but I digress), but like, honestly? Let's just go through the list of pain that we now have context for.
Let's start with the whole group. Assuming they have no more information than the audience, they have no idea where Nat is.
--Oh no. They probably don't even know what side she's on, right? She helped Steve escape with Bucky but the only people who saw that were Steve and Bucky, and then the people on Team IM, who think she betrayed them. The people she put herself out there for don't even know she put herself out there for them.
And now they're in extrajudicial sea prison and- if I'm remembering the third act of CW correctly, which to be fair I may not be because I usually quit after act 2, and I assume someone will correct me if I'm wrong- while they wonder about whether Steve might come save them, no one even considers Nat would. Because they think she was on the other side? Because they think she wouldn't care? Because they know she's a regular human being and that makes it damn hard to take down governments? Because they assume she'd keep her circle small? Like every single possible reason behind that assumption is a world of pain directly contradicted by the events of BW, which they will never know about. Which hurts.
And at the beginning of the movie, she didn't seem to want to break them out! Like, she kept insisting she was better without a team. Obviously, she was denying her emotional attachments to make things hurt less- and obviously she has a lot of baggage around what it means to be a team and what it means to be family and whether any of them would look for her- but she was in fact actually kind of being the person they thought she was. Like it sucks when people have a bad view of you but it sucks in an entirely different way when their negative view of you is based in reality. It's a brutally harsh look in the mirror.
(And I think this is where the events of BW most change Natasha; I think that any belief she might have had that if she could get out of situations anyone could if they really want to got a rude awakening when it turned out her escape from the Red Room directly led to the other women not being able to, and I think that's shock to her system that she desperately needed. This movie more than anything showed me some of Nat's flaws and I love it for that.)
And then you have to consider that, at least 2 weeks before this (because the jet scene was 2 weeks after the Red Room takedown), she broke Alexei out of the gulag. Like, she did what she had to to take the Red Room down, there's absolutely no faulting her for that, but imagine seeing all your friends stuck in high-security prison and knowing that you had the capacity to break people out of those, in fact did it less than a month ago, but left them there. Again, this is not me saying that she did the wrong thing, but imagine the guilt on her end!
We have Wanda, who's about Yelena's age, the only woman on the Raft, being forcibly restrained far more than any of the men are- how does that not conjure up memories? And then on the other hand it's Wanda, who has the ability to manipulate memories and impulses, who is basically the organic version of what Dreykov did! AND she's the one who brought back Red Room memories Nat clearly didn't want to deal with during Ultron and clearly hadn't processed by this point! How fucking confused must Nat's feelings about Wanda be at this point? She's simultaneously what Nat wants to protect and what Nat wants to protect from, and she's sitting there immobilized in prison in a fucking straightjacket.
And then we have Clint and Scott, which, OKAY. I was talking to @sidewaystime about which Avengers Alexei and Melina mirror (it was an EXCELLENT conversation, it gave me a lot of feelings, but I digress), and she pointed out that Alexei considered himself trapped during the assignment with Nat and Yelena and was complaining about how terrible it was even after (we assume) over a decade in a literal Russian gulag, while we know that Steve and Nat rescued Wanda and Sam but Scott and Clint were both willing to stay behind and deal with the government because they'd rather risk jail than not see their kids again. Like repeatedly through the MCU, Clint and Scott explicitly and repeatedly choose family over everything, immediately after Nat had to confront the people who threw her and Yelena away two decades ago and also had to confront the fact that she essentially did the same thing to Yelena. And here's Scott and Clint representing exactly what she wishes had been done to her, and/or that she'd done!
And all of this, all of this, is stuff none of them know. Given that in Endgame both Steve and Clint assert her only family was the Avengers, she never let them know the foundation of her world had been this shaken and they were all embodying parts of that to her! And she was presumably just putting those feelings in the Feelings Box where we work very hard to pretend they don't exist, while she's piloting a plane and waiting for a group of superheroes to re-board it from the prison, which has to bring back feelings from both Yelena holding the plane while she gets Alexei and from when she was fucking ten years old flying to Cuba with her dad surrogate on the wing with a gun and her mom surrogate bleeding out.
Even Sam, who probably prompts the least trauma for Nat (his closest mirror is Yelena, not Alexei or Melina) and who has the best idea of how to interact with other human beings, who would probably be respectful of triggers, has no idea she even has these triggers! So it's not like anyone can protect her, because she's not giving them the necessary information to do so and so it's all just ENDLESS MINEFIELDS.
Literally everything from the end of Civil War hurts more now!
Just imagine if any of that had been intentional.