PHP - Load 404 page for non existing articles wihout changing URL

Question

I know there are many similar questions on this and I've read them and no they didn't work. I want to show 404 page when a non existing dynamic url is accessed on my website but without changing the url. For example:

https://www.trvme.com/destinations/corbett

is fine. But if I enter an invalid link like

https://www.trvme.com/destinations/corbetts

I get browser's 404 error but I don't see my 404 page. Here's the code I have in PHP

if(isset($_GET['destId'])){
    $link = mysqli_real_escape_string($connect, $_GET['destId']);
    $thisPage = 'destinations/'.$link;

    $query = "SELECT * FROM `destinations` WHERE `link` = '$link' AND `active` = 1 AND `delete` = 0";
    $destinationsQuery = mysqli_query($connect, $query);
    if(mysqli_num_rows($destinationsQuery)!=0){
        // do stuff
    } else {
        http_response_code(404);
        exit();
    }
} else {
    http_response_code(404);
    exit();
}

And htaccess

RewriteEngine On

ErrorDocument 404 /message.php?id=2

RewriteRule ^destinations/(.*)$ destinations.php?destId=$1 [NC,L]

I don't want to use header('location:message.php?id=2'); in php because that would change the URL. I'm getting 404 code from the URL but htaccess doesn't seem to be doing its job.

I also can't use

http_response_code(404);
include 'message.php';

because it throws all kinds of errors like session has started already and constants have been defined already. That doesn't seem like an elegant solution.

Edit:

The code in the linked question doesn't work for me. If I add the code above the destinations rule, the existing, legitimate pages also go to 404 because there's no actual file or directory, these are dynamic urls.

RewriteEngine On

ErrorDocument 404 /message.php?id=2

RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ /message.php?id=2 [L,NC]

RewriteRule ^destinations/(.*)$ destinations.php?destId=$1 [NC,L]

If I put it afterwards, it just doesn't work because the destinations rule takes over

RewriteEngine On

ErrorDocument 404 /message.php?id=2

RewriteRule ^destinations/(.*)$ destinations.php?destId=$1 [NC,L]

RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ /message.php?id=2 [L,NC]

Answer 1

if you want a specific 404 you need to catch it or create the 404 HTML that is loaded within apache.

look at: catching all invalid URLs

They've suggested using the ErrorDocument within the apache.