What do you mean when you say 'the default product variables are not visible in the report suite'? Is it specifically the 'Product' report, or others as well? Is the 'Product' variable itself mising from the menu, or is it just blank?  On the above hit, if I remember correctly, this will not add to ...

It's a while since I've used RP extensively, but does the report refresh manually within Excel? Is there a date range in the schedule/report in the future, so is it waiting for data before completing the refresh? 

That might get you a more Launch-focused answer, yes: https://experienceleaguecommunities.adobe.com/t5/adobe-experience-platform-data/bd-p/experience-platform-launch-qanda However, if you've installed that global site tag extension already, then be aware it's a 3rd party extension, not one created b...

Just to be clear, are you referencing an extension in Launch or Experience Platform? The link you've got there refers to an Experience Platform connection, but the Google Global Site Tag is a Launch extension (& would be why you can't see a Google Ads extension).