<?php
$data1 = new DateTime('first day of 2 months ago');
$data1->setTime(0, 0);
var_dump($data1->getTimestamp());
$data3 = new DateTime('2020-09-01');
var_dump($data3->getTimestamp());
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
int(1598911200)
int(1598911200)