The logout confirmation which may state like if you are sure to logout, click on... is not coming from BuddyBoss. It maybe from other 3rd party plugins installed on your site. At any rate, you can try to add the Function.PHP code on your activated Theme's function.php. We do not have a specific setting for this on the Platform. 

Please try adding the below Function in your theme files by following these steps:

1. Go to Appearance > Theme Editor

2. Under “Select theme to edit”, choose (BuddyBoss Child/Whatever theme is active), then click “Select”.

3. Below Theme Files, select Theme Functions (functions.php).

4. Append the following just before the closing PHP tag “?>”:

function custom_logout_redirect() {

    wp_redirect(home_url()); // Redirect to homepage, change this URL if needed

    exit();

}

add_action('wp_logout', 'custom_logout_redirect');

5. Click “Update File” to save the changes.

Note: Any modifications are considered custom work already. Know more about our Support policy here: https://www.buddyboss.com/support-policy/