hi @shyams67489715 - assuming that your product-catalogue contains multiple products and you would like to show the banner mentioned in step 3 dynamically, there could be 2 options:
1. Use Adobe Target Recommendations: Upload the meta-data about all products to Recommendations. On the PDP page, pass the product-id of the product to Adobe Target. On the landing page, setup a Recommendations based activity using "most recently viewed product" and create the banner as Recommendation design.
This will be a completely scalable solution as you can keep adding/removing products to product-catalogue.
2. Using AEM Fragments: I am not an AEM expert - however the possible solution would be to pass the last viewed product-id to AEM (you can store that in cookie) and then map it to Experience Fragment. If the number of products is high, you may have to create loads of mappings between products and experience fragments.