I think what makes Peeta/Katniss unique in terms of ya romance is that a lot of their development occurs on the emotional level. Instead of having a relationship that basically has your couple meet, then fall in love (HOW???), then spend the rest of the series defending their eternal teenage love against all manner of complications, Peeta and especially Katniss internalize a lot of ther true emotions and spend three books mainly concerned with staying alive, making their development a lot more natural and realistic (given the circumstance they’re in).
I love that their relationship is complex and full of layers (how is Everlark like Shrek???). Straight away you have their connection as children and Peeta’s pre-existing feelings, then you add on to that their weird alliance as tributes with Katniss trying to remind herself she may have to kill him, then Peeta brings in the media component during his interview, meaning whether or not she has true feelings for him, Katniss has to play the star crossed lover anyway. AND THIS IS LIKE THE FIRST HALF OF THE FIRST BOOK ONLY.
And then come the cave scenes and Katniss realizes that this kid has been trying to help her all along (help, not save - Peeta never tries to swoop in and rescue Katniss, he knows perfectly well that she doesn’t need him), and for someone who has been forced to take on the burdens of supporting a family, who relies on her own strength and nothing else, this completely floors Katniss. I honestly think the concept of someone loving her unconditionally is crazy to Katniss.
A lot of their relationship is defined or developed in the arena/when they think the other is in danger (both acknowledge that they would rather die than suffer the emotional fallout of losing each other, which fucking COME ON NOW), but on a more surface level, Katniss and Peeta genuinely like each other. Katniss and Haymitch and even Gale often speak about how likeable Peeta is - there’s this passage in Catching Fire where Katniss talks about being in school and seeing Peeta sitting with a huge group of friends at lunch while she sat alone. Which 1. Katniss stop scoping out Peeta you two are like fourteen shit up and 2. is one of many things Katniss thinks about re: Peeta and his personality, which she admires because she considers it the opposite of her own cold demeanor.
Even though Peeta is still from District 12 and lives on the shit side of life, Katniss sometimes resents him for not being from the Seam and thus not truly understanding how hard life can be, but at the same time this attracts her because Peeta has always symbolized hope to her. Katniss is attracted to Peeta’s kindness, his (relative) innocence, the way he is optimistic when she can’t be. This more than anything is what Katniss mourns when he comes back in Mockingjay; the fact that the boy who threw her bread and had never been cruel to anyone had been tortured beyond standing and that she considered herself to blame. This is why Katniss cannot kill him, why she tries to keep him alive in Catching Fire - because she considers Peeta to be truly good, unlike most of the people she knows.
As for Peeta… well, he’s just crazy about Katniss tbh. He loves her for all th reasons the reader loves her - her courage, her strength, that insular part of her that led her to volunteer for Prim, to sing for Rue.
Peeta’s defense is his charm and the way he can spin things - many people note this about him, and attempt to use him as a propaganda tool in the way they could never use Katniss. And he uses that skill as much as he can to try and help Katnias survive both arenas. Which would be pretty damn painful when he finds out that Katniss has been faking, but he does it anyway because he loves her, plain and simple.
It’s incredibly telling that through everything that happens in these books, through all the trauma and the pain and loss that these two kids to through, that thier relationship survives, and flourishes and grows and becomes a part of who they are. AND THOSE ARE MY EVERLARK FEELS. Also braid touching.