Asus says it's ok to use generic USB-C adapters to recharge the laptop in spite of the warning label telling owners otherwise. When charging via the AC barrel port, however, be sure to use only those provided by Asus.
https://www.notebookcheck.net/Asus-clarifies-that-confusing-warning-label-on-the-Zephyrus-Duo-15-about-battery-charging.519548.0.html