how to reduce AWS SES bounce rate with respect to QA environment automation scripts

Yes. As you are aware that, Amazon SES watches hard bounces closely. They start complaining when the rate is above 5%, and any rate greater than 10% might disable your account from sending emails. Apart from this probation, they might suspend your account. Few things are :-

1)Refrain from buying, renting, or scraping an email list. It could contain inactive addresses, thereby increasing the bounce rate of your Amazon SES campaign. 2)Always use double opt-in. It requires two-way confirmation before any email account is added to your mailing list. A confirmation email will be sent to the submitted email account. This will ensure you are sending emails to people who really want your emails and the chances of being spam and email bounce is very low 3)Use an effective call-to-action button and make sure your landing pages are intact. 4)Always use a bulk email validation service to tidy up your list. Amazon SES recommends starting your marketing campaign only after your mailing list has been verified with an email verification tool. 5)Remove subscribers who are not interested in your business or product. 6)Remove addresses that have already bounced back an email message.

Hope this helps.