There's no version of it, but the solution isn't hacky at all.

$pos = strpos($haystack, $needle);
if ($pos !== false) {
    $newstring = substr_replace($haystack, $replace, $pos, strlen($needle));
}

Pretty easy, and saves the performance penalty of regular expressions.

Bonus: If you want to replace last occurrence, just use strrpos in place of strpos.

Here it is as a reusable function:

/**
 * Like str_replace, but only replaces once.
 * 
 * Example:
 * <code>
 * // $replaced: 'I have 50 dogs and 100 cats'
 * $replaced = str_replace_first_instance('I have 100 dogs and 100 cats', '100', '50');
 * </code>
 */
function str_replace_first_instance(string $haystack, string $needle, string $replacement_text): string
{
    $needle_position = strpos($haystack, $needle);
    
    if ($needle_position !== false)
    {
        $haystack = substr_replace($haystack, $replacement_text, $needle_position, strlen($needle));
    }
    
    return $haystack;
}

Example usage:

//This will return 'I have 50 dogs and 100 cats'
str_replace_first_instance('I have 100 dogs and 100 cats', '100', '50')