How to use PHP to determine if it is a Friday at the end of the month

<?php
$date = strtotime("2021/06/25");

// Compared to Friday at the end of the month
if($date==strtotime("last of this month",$date)){
    "Echo" Last Friday.\n";
}

// Day of Week Comparison & Compare Current Month to Next Week Month
if(date('w',$date)==5
   &date('m',$date)!=date('m',strtotime('+1week',$date))){
    "Echo" It's the last Friday.\n";
}
?>

<?php

require 'Carbon/autoload.php';

use Carbon;
use Carbon\CarbonPeriod;

$day='2021-07-15';
// $day = Carbon::now();
$period=CarbonPeriod::between(
    Carbon::parse("first of {$day}"),
    Carbon::parse("last free of {$day}"),
  )->weeks();

foreach($period as$date){
  $fridays[] = $date->format('Y-m-d');
}

echo implode(PHP_EOL, $fridays).PHP_EOL;
echo PHP_EOL;

$last=Carbon::parse("last day of {$day}")->subDays(3);
$month = $last->format('Y/n');
foreach(range(0,2)as$offset){
  $date = $last->addDays(1)->format('Y-m-d');
  echo "{$date}is".
    ($date==end($fridays)?':'not').
    "last Friday of {$month}".PHP_EOL;
}

# execution result
2021-07-02
2021-07-09
2021-07-16
2021-07-23
2021-07-30

2021-07-29 is not last Friday of 2021/7
2021-07-30 is last Friday of 2021/7
2021-07-31 is not last Friday of 2021/7