Function bevy_time::common_conditions::once_after_delay

pub fn once_after_delay(
    duration: Duration
) -> impl FnMut(Res<'_, Time>) -> bool + Clone

Run condition that is active once after the specified delay, using Time to advance the timer. The timer ticks at the rate of Time::relative_speed.

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(
            Update,
            tick.run_if(once_after_delay(Duration::from_secs(1))),
        )
    .run();
}
fn tick() {
    // ran once, after a second
}