Hello! I have also been on fiverr for a little more than 30 days now and I am experiencing the same problem as you. On my buyer requests section, it says no requests found. That may be because there really aren't any requests, but I doubt that's the case when I offer data entry and data processing services.
About Buyer Briefs, I have had two matches until now; so I guess that works for us new sellers.
With what I have read here on the forum, Instagram and LinkedIn are the best platforms to promote your gigs (but I personally haven't tried any social marketing strategy yet).