You are correct QA is useful if you want to test visual changes. For your needs I would set up a gatekeeper audience that only allows people in if the URL contains adobetest=123 or whatever other secret parameter you want to use. This way you will be able to test on live and see actual results etc.
If this satisfies your query please like, mark as helpful and mark as answer. Otherwise lets keep the conversation going. Hope you have a wonderful day.
the preview QA link will only help me with the UI/Design testing. How can i test if my criteria, feeds and mbox paramter is properly implemented so that correct products will be shown in the design/UI which has been created