I think a big part of why aftg (the original triology) so often gets referred to as bad writing is because the language is a bit plain. It does have some absolute bangers, but compared to Jean's way with words, a lot of Neil's inner monologue is rather straightforward.
Which is probably largely due to Nora's writing evolving over a decade, but it also works so well inverse.
Given that Neil never was allowed to see the beauty in anything because it was considered dangerous, and was scrutinised by his mother from a very young age to make sure his sole focus was survival, his one track mind makes sense.
Jean, meanwhile, was punished for every little action and behaviour his abusers didn't like while also being told over and over that he himself had no value, but no one ever cared about him enough to warn him of the world. He was not allowed a lot, if any, positive experiences while in the Nest, and he was not allowed to actively want things, but unlke Neil he was never taught to fear pleasure because it itself was a risk, only because he might be punished for it.
Therefore, when they are both free out in the world, it makes sense that Jean is faster to see and express beauty, while Neil takes longer before he can see happiness as anything but bait for a trap.