@lavaclient/plugin-effects

import type { PlayerEffect } from "@lavaclient/effects";

const nightcore: PlayerEffect = {
    id: "nightcore",
    filters: [
        {
            type: "timescale",
            data: { rate: 1.125, pitch: 1, speed: 1 },
        },
    ],
};

await player.effects.toggle(nightcore);