Man, Bryce's chapters are such a slow burn, and that's what makes them work. For most of the book, he's just this oblivious kid coasting on his family's weird snobbery and his own good looks. His perspective early on is all surface-level annoyance at Juli's 'stalker' behavior and a shallow fixation on social standing, like with the eggs. The change isn't a light switch; it's a series of uncomfortable realizations that chip away at his worldview.
It starts with small things, like his guilt over the eggs and the trash yard, but the big shift comes from his grandfather, Chet. Seeing Juli through Chet's eyes—as someone with genuine substance, the 'sunlight'—forces Bryce to confront his own family's pettiness, especially his father's bitter jealousy. The climax is him finally understanding the Sycamore Tree, that it wasn't just a tree to Juli but a way of seeing the whole world. His perspective flips from judging Juli to judging himself, realizing he's been the one who was 'flipped' all along, living upside-down in a world of his family's making. He ends the book actively trying to replant that tree, which is a pretty solid metaphor for trying to rebuild his own perspective from the roots up.