Sound's Edge. Echo Forge, #1

Sound's Edge follows Dominic Wells, a gifted sonic craftsman in Parallax a city fragmented across multiple timelines. Known as Echo Forge, Dominic shapes solid constructs from sound, keeping chaos at bay. But when a series of time anomalies disrupt the city, he discovers a chilling truth: an alternate version of himself, Dominus, is collapsing timelines to create a singular, "perfect" reality. Recruited by the Temporal Assembly, guardians of timeline integrity, Dominic begins hunting his dark counterpart, only to uncover that Dominus was once the original while Dominic himself may be a manipulated replacement.
As Dominic unravels the secrets of Parallax, he's forced to confront fractured versions of himself, question his memories, and choose between order and freedom. He learns that the Temporal Assembly has curated his life, pruning other Dominics for being unstable. When Dominus attempts to merge all timelines using a powerful artifact the Harmonic Key Dominic must forge a new sonic weapon and confront his darkest self in a collapsing city of echoes.
The book ends with a twist: Dominus survives and is joined by a mysterious third version of Dominic. As a new tone not tied to any known timeline plays, Dominic hears the words: "We were waiting." The fracture has only just begun.