Have you uploaded your dynamic creatives in Google Studio but only one dynamic product is displaying in the preview? Most probably, you need to change a setting in your Dynamic Content profile in Google Studio.
Follow the steps to resolve the issue you're facing:
Log in your Google Studio account and select the Profile where you uploaded the Dynamic feed under "Dynamic Content".
Click on Step 2 “Manage data”.
You now see a field named “Quantity”. By default, this is always set to 1.
Simply change that number for the amount of dynamic product your ad design contains. For example, if the creative contains 4 slides and each slide shows 1 dynamic product, fill in a “4” in the field.
Click on “Save & continue”.
Click now check on Step 5, "Preview".
Your ads will now show the different dynamic elements added in the design.
We hope the information in this article was useful to achieve your goal. If there is anything else we can help you with and you couldn't find it in our help center, don't hesitate to contact us by chat.