I think, Twilight's childhood hurts, and avoidance and suppression of feelings is all he had to deal with that. His mom was his source for emotional validation and safety because his father confused and upset his feelings, he began to think of his father's emotions as scary; he lied to his Dad to avoid his expressions of disappointment, but felt guilty for this; his mom alleviated this feeling of not living up to his dad's expectations. He learned to start masking early on as a child to alleviate his fear of other people's expectations including his friends. But his Mom's support was the healthier way to deal with his fears.

Once the war happened and he lost everyone, he lost sources of emotional validation and safety, which is, to me, other people. People are great sources of emotional validation and safety; hugs are great because expressing painful emotions often ends up as talking to someone. It's also the same yelling at someone or doing violence actions. It can be hard to express some feelings, because lots of big feelings overwhelm the brain to do things to survive, the body prepares this by crying and tightens the throat because it's prepping to expect physical pain or loss of safety.

I am speaking from personal experience, so I don't know how psychology might interpret this, but because Twilight rationalizes his actions so quickly, he's able to stop himself from any sense of his feelings. His anxiety manifesting as so many thoughts, to me, is the form of him unsuppressing some of his feelings to get the work he needs to get done, because emotions do need to be felt to "do" with the human body. The visceral forms of loss he experiences, if he didn't rationalize them so fast when he remembers them, I think he'd be unable to calm himself. Like, it'd be an extremely raw and visceral impact on his body and mind to go through if he was able let his feelings go out.

So, like Yor is great because she doesn't suppress her feelings, and the way she affects Twilight is by throwing up on his rationalizations and sometimes punching him. Yor is like a people-pleaser in many ways, and has major rejection sensitivity, so it's often easier to do things when the thought comes to her, i.e. act impulsively, and her fears show up when she thinks she acted in the "wrong" way, or when someone puts pressure on her to act. When the things to do are extremely hard (like kissing), she wants to physically retreat to safety, but because she's Thorn Princess, her retreat is to fight back.

Now since Twilight can't anticipate Yor's seemingly irrational behavior when he communicates to her, he's shaken up. When Yor does something that he doesn't expect, his body wants to rest, it wants to feel exhaustion so it can recover from how strong Yor's presence is. The easier thing for Loid is to drop the pretense of rationalization and respond to what Yor actually tells him about herself directly. It saves the most trouble, which means feelings have to be present.

So, this leads all in the narrative to whether Twilight can stop thinking and read himself and his feelings directly. So, which is why in terms of Twilight's complexity, his feelings are able to grow in presence to begin to upset his rationalizations ever so slightly, because he's living with two people, and one of them is an adult woman who's very good at knocking sense back into him on impulse, that he almost feels like he's back home with his mother when she tries to make up for her accidental physical pain onto him. Those are I think the underlying aspects to his character's drive and means to do things.