Wolf Tooth Disc Brake Adapter - Post to Flat Mount, +20mm - Pro Bike Supply
Amazon.com: SwishTi Cyclocross Gravel E-Bike Bicycle Bike Flat-Mount Disc Brake Adapter for Flat-Mount Forks and Post-Mount Calipers use w/2pcs FM Bolts : Sports & Outdoors
Flat Mount and 180mm discs: yes you can! - YouTube