<?php
$array = [
['ID' => 1, 'title' => 'Boring Meeting', 'date_start' => '2010-07-30', 'event_type' => 'meeting', 'state' => 'new-york'],
['ID' => 2, 'title' => 'Find My Stapler', 'date_start' => '2010-07-22', 'event_type' => 'meeting', 'state' => 'new-york'],
['ID' => 3, 'title' => 'Mario Party', 'date_start' => '2010-07-22', 'event_type' => 'party', 'state' => 'new-york'],
['ID' => 4, 'title' => 'Duct Tape Party', 'date_start' => '2010-07-28', 'event_type' => 'party', 'state' => 'california']
];
usort($array, fn($a, $b) => [$a['state'], $a['event_type'], $a['date_start']] <=> [$b['state'], $b['event_type'], $b['date_start']]);
var_export($array);
preferences:
58.79 ms | 405 KiB | 5 Q