How Change Wordpress header image from admin menu

I have created a section inside the admin menu, Where it is possible to upload the logo, How can I replace this uploaded image with wordpress logo(header_image())? //admin dashboard page

img alt= src=?php header_image() ?
        form action=?php echo get_stylesheet_directory_uri() ?/process_upload.php method=post enctype=multipart/form-data
            Your Logo: input type=file name=profilepicture size=25 /
            input type=submit name=submit value=Submit /
        /form

//upload process code

?php
require( dirname(__FILE__) . '/../../../wp-load.php' );
$theme_root = get_theme_root();
$wordpress_upload_dir = wp_upload_dir();
$i = 1; 

$profilepicture = $_FILES['profilepicture'];
$new_file_path = $wordpress_upload_dir['path'] . '/' . $profilepicture['name'];
$new_file_mime = mime_content_type( $profilepicture['tmp_name'] );

if( empty( $profilepicture ) )
    die( 'File is not selected.' );

if( $profilepicture['error'] )
    die( $profilepicture['error'] );
    
if( $profilepicture['size']  wp_max_upload_size() )
    die( 'It is too large than expected.' );
    
if( !in_array( $new_file_mime, get_allowed_mime_types() ) )
    die( 'WordPress doesn\'t allow this type of uploads.' );
    
while( file_exists( $new_file_path ) ) {
    $i++;
    $new_file_path = $wordpress_upload_dir['path'] . '/' . $i . '_' . $profilepicture['name'];
}

// looks like everything is OK
if( move_uploaded_file( $profilepicture['tmp_name'], $new_file_path ) ) {
    

    $upload_id = wp_insert_attachment( array(
        'guid'           = $new_file_path, 
        'post_mime_type' = $new_file_mime,
        'post_title'     = preg_replace( '/\.[^.]+$/', '', $profilepicture['name'] ),
        'post_content'   = '',
        'post_status'    = 'inherit'
    ), $new_file_path );

    // wp_generate_attachment_metadata() won't work if you do not include this file
    require_once( ABSPATH . 'wp-admin/includes/image.php' );

    // Generate and save the attachment metas into the database
    wp_update_attachment_metadata( $upload_id, wp_generate_attachment_metadata( $upload_id, $new_file_path ) );

    // Show the uploaded file 'in browser
    wp_redirect( admin_url( '/admin.php?page=coalition-setting' ) );

}