Drupal 8.x

The site I am working on belongs to Drupal 8.9.13 version. Our web scan has come up with an issue as:

Credential Management: Sensitive Information Disclosure. Web scan has detected the presence of username and/or password in http traffic when accessing some URLs in our site. For example when we go to https://oursite/about and do a view page source, we could see the username and token like below:

Introduction: I was struggling with slow ajax requests in a custom module form.  Since I couldn't find any good resources I wanted to share my solution.

How can we avoid displaying sql stack trace on page

SQL stack trace on page-

Security scan trying to manipulate form_build_id value to something else

e.g 

form_build_id manipulated from: form-i0JR1J8PhobAlL1_m6CQ8oHm02Ogf5Z-Gfd9XClh5PU to: form-i0JR1J8PhobAlL1_m6CQ8oHm02Ogf5Z-Gfd9XClh5PU%a5'%20having%201=1--%20

manages to produce sql stack trace on page (UI) showing details of Drupal's SQL entities/ tables

e.g.

I have been trying so long for this to work, before it always used to work with my old computer. With the new one I seem to be unable for it to work.

Composer works fine but Drush seems to not work, I am having an issue where: