Function bevy::time::common_conditions::once_after_real_delay

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

Run condition that is active once after the specified delay, using Time<Real> to advance the timer. The timer ticks are not scaled.

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
}