index.php

<?php
/**
 * @author Joubert RedRat
 * https://3v4l.org/m7Mp9
 */

function getDateNow(): ?\DateTime {
    $datetime = new \DateTime('now');
    
    $minute = (int) $datetime->format('i');
    return $minute % 2 === 0 ? $datetime : null;
}

function getUpdatedEarly(): \DateTime {
    $d = getDateNow();
    if (!$d instanceof \DateTime) {
        throw new \Exception('oooops by early');
    }
    
    return $d;
}

function getUpdatedEarlyCoalescing(): \DateTime {
    $d = getDateNow();

    return $d ?? throw new \Exception('oooops by coalescing');
}

try {
    $d = getUpdatedEarly();
    echo $d->format('Y-m-d H:i:s');
} catch (\Throwable $e) {
    echo $e->getMessage();
}

echo PHP_EOL;

try {
    $d = getUpdatedEarlyCoalescing();
    echo $d->format('Y-m-d H:i:s');
} catch (\Throwable $e) {
    echo $e->getMessage();
}