To implement this use case, you will need:
Step 2: Create a Visitor Scoped Badge to assign when the Visit Scoped Number Attribute equals 3
Step 3: Create an Audience based on the Badge you just created.
After that, you should be all set. Hope This helps!!
My apologies, I completely overlooked that you wanted to activate the audience within the time frame of 7 days. To do there are 4 steps:
Step 1: Create a Visitor Scoped Timeline Attribute to capture when a customer visits a PDP page and expires after 7 days
Step 2. Create a Visitor Scoped Number Attribute that captures that enriches by capturing the number of entries in the timeline
Step 3. Create a Visitor Scoped Badge Attribute that enriches based on the Number Attribute
Step 4. Create an Audience based on the Badge
Please let me know if this helps!