Ranking # 1 in google with Google drive link ! how ?

How is it that my competitor is ranking # 1 with a google drive link.. I'm competing on a very low comp, with a high search volume, first page is mostly google drive and pdf links, and the two niche sites on the first page are 3-4 months old. doesn't have any spam on either of their Backlink profiles, seems like more of PBN links pointing at them. my main KW is more than 25,000 searches / month... I'm done building my niche site, just wanted to get some light from the pro's , what would be the some suggested strategies to break this first page competition

btw has anyone done this before, ( ranking google drive link ) .. and how can u monetize with such downloads ?

thanks in advance