If the event is reported in one report suite and not in another, there must be some difference in the processing rules. 

Looking at your initial query, it gave me the impression this was about the Site Section variable. I see now that you are referring to Products. If you need to restructure the sections (classifications), you can start with adding new classifications for the Products variable. Add sub classifications...

I will assume you are recording button clicks in a Custom Event (Page diemension will not record Custom Links). You can use a segment as below and use it in a report with the customer event (metric). 

I will suggest using Optin services in Experience Cloud ID to create cookies only for specific domains.

I would suggest creating a classification for Site Sections and upload classification values using SAINT importer.

You can drag and drop Day dimension from left rail to to one of the tracking code items or use Data Warehouse report with Daily granularity. See below.   

See my reply.

If you are using Visits as metric in the evar report and see an increase in the number of Unspecified, this must be due to evar values not being set in the hits. You may want to check for Pages which contributed to most of the Unspecified visits and check the code/set up on why the value would not h...

Check this out: analytics-2.0-apis/examples/jwt/java at master · AdobeDocs/analytics-2.0-apis · GitHubDoes that help?

Break down Tracking Code dimension with Day.