Validating whatsapp webhooks Payloads in laravel

I'm trying to validate the contents of a webhook payload from the whatsapp webhooks using the steps in the .Facebook developer docs,

I dont understand what this mean

Please note that we generate the signature using an escaped unicode version of the payload, with lowercase hex digits. If you just calculate against the decoded bytes, you will end up with a different signature. For example, the string äöå should be escaped to \u00e4\u00f6\u00e5.

that why I've always got false when comparing hash value And i want to make it in php/laravel.

after sometimes i tried to use

            $knownSignature = (new UnicodeString($request->getContent()))->normalize(UnicodeString::NFKC);

and

$knownSignature = Str::ascii($request->getContent());

But still doesnt match. event when i tried to convert äöå it still outputting \u00e4\u00f6\u00e5

This is Symfoni and Laravel docs for escape unicode string

I've done just like @CBroe said it did not work in my previous function, but when I remake it like this its works

protected function validatePayloads(string $waSignature,string $payloads){
    $receivedSignature = explode('=', $waSignature)[1];

    $generatedSignature = hash_hmac(
        'sha256',
        $payloads,
        config('app.app_secret')
    );

    if($receivedSignature == $generatedSignature){
        return true;
    }else{
        return false;
    }
}

Just like @CBroe said you need to hash the raw request