The OnePlus 6 is now the most commercially successful device released by OnePlus. The phone hit one million uints sold within the first 22 days of its release, in spite of its higher price tag and OnePlus's continued "underground" approach to marketing and retail.
https://www.notebookcheck.net/The-OnePlus-6-sold-more-than-one-million-phones-in-its-first-22-days-on-the-market.308932.0.html