Can anybody explain why this php code is not excluding the watched_videos?

Can anybody explain why this php code is not excluding the watched videos?

the email_id is for specifying where to find the watched videos array.
i want the code to remove watched_videos array from the user table. the watched_videos array is stored as a string so it need to be converted to an array. is there a way i can make this code work.
i want the code to exclude watched videos when the video_id are being sent back to an ajax request.
here is the code:

<?php

// Database credentials

$servername = "localhost";

$username = "root";

$password = "";

$dbname = "refwebsite";

// Create connection

$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection

if ($conn->connect_error) {

die("Connection failed: " . $conn->connect_error);

}

// Get the start and limit parameters

$start = 1;

$limit = 12;

$email_id = "[email protected]";

// Get the watched_videos array for the user with the given email_id

$sql_watched = "SELECT watched_videos FROM users WHERE email_id='$email_id'";

$result_watched = mysqli_query($conn, $sql_watched);

$row_watched = mysqli_fetch_assoc($result_watched);

$watched_videos = explode(",", $row_watched['watched_videos']);

// Generate a comma-separated list of unique_id values to exclude

$exclude_list = implode(",", $watched_videos);

// Select two random videos from the "less_videos" table, excluding watched videos

$sql_less = "SELECT video_id, description, points FROM less_videos WHERE unique_id NOT IN ('" . implode("', '", $watched_videos) . "') ORDER BY RAND() LIMIT 2";

$result_less = mysqli_query($conn, $sql_less);

// Select ten random videos from the "more_videos" table, excluding watched videos

$sql_more = "SELECT video_id, description, points FROM more_videos WHERE unique_id NOT IN ('" . implode("', '", $watched_videos) . "') ORDER BY RAND() LIMIT 10";

$result_more = mysqli_query($conn, $sql_more);

// Combine the selected videos into a single array

$data = array();

while ($row = mysqli_fetch_assoc($result_less)) {

$data[] = $row;

}

while ($row = mysqli_fetch_assoc($result_more)) {

$data[] = $row;

}

// Shuffle the array to randomize the order of videos

shuffle($data);

// Extract the required subset of videos

$data_subset = array_slice($data, $start, $limit);

// Return the data as JSON

echo json_encode($data_subset);

// Close the connection

mysqli_close($conn);

i tried finding the problem but i did not.