Month equivalence and unit restriction in forHumans function

I'm encountering two peculiar behaviors with a library, and my objective is to convert seconds into a readable format displaying days, hours, minutes, and seconds.

When attempting to convert 2698447 seconds into a human-readable format using the Carbon library, I obtain the following result:

<?php

use Carbon\CarbonInterval;
use Carbon\Carbon;

echo CarbonInterval::seconds(2698447)->cascade()->forHumans();

However, when using an online converter, the output is different (https://www.tools4noobs.com/online_tools/seconds_to_hh_mm_ss/):

In my code, I also experimented with CarbonInterval, and when converting 28 days and 30 days separately, the output seems to imply that 28 days is equivalent to a month:

use Carbon\CarbonInterval;
use Carbon\Carbon;

echo CarbonInterval::seconds(28*24*3600)->cascade()->forHumans(); // Outputs: 28 days
echo "\n";
echo CarbonInterval::seconds(30*24*3600)->cascade()->forHumans(); // Outputs: 30 days
echo "\n";

Considering these results, I am puzzled about the interpretation of days as a month. How can I configure the conversion to consider a month as 30 or 31 days, and furthermore, is it possible to restrict the output to days as the maximum unit (days hours minutes seconds)?

You can skip the units you don't want in the forHumans() options:

echo CarbonInterval::seconds(2698447)->cascade()->forHumans([
    'skip' => ['week', 'month', 'year'],
]);