"Reverb" appears to refer to a rhythm/action game (possibly the VR title Reverb or a lesser-known indie). Regardless, **no official cheat codes exist**, and third-party "hacks" are universally risky.
Clarify the exact title (platform, developer, year). A different game might have:
But for any rhythm-based "Reverb": the only cheat is practice. The satisfaction of nailing a hard chart cleanly is the entire point.