Page request fails to load debug toolbar.

I just found the solution to this question. If it helps anyone else, here's what I did wrong:

During apache setup I found I had to use port 8080 instead of port 80. So, I replaced the default line in my httpd.conf file, "#Listen 12.34.56.78:80" with "Listen 8080".

My error was that I did not also add the port number in my browser request URL and in the $baseURL in .env file to httpd://localhost:8080/MZCI4/public Both of these appear necessary.

Also, it turns out that I did not change the line public $baseURL = http://localhost/MZCI4/public in my app/Config/App.php file to public $baseURL = 'http://localhost:8080/MZCI4/public/';

But changing that line has no effect because the .env entry supersedes the app Config entry, as I would expect. Still, I changed it to match the .env file for consistency.

Now the page loads in 150 ms and includes the debug icon and functions.

Hope that helps someone.