Complain to Fortnite. They have a known issue from the last update, it's not AMD it's them. When you installed the newer driver did you use DDU or the AMD tool/Factory reset option? Here's the link for DDU: Display Driver Uninstaller Download version 18.0.3.6 (guru3d.com)
Run that in safe mode and reinstall the newer AMD driver that you can download from: AMD Radeon™ RX 6800 XT Previous Drivers | AMD
It might clear it up so the game launches.
"It worked before you broke it!"