If you're playing on Steam, this should just work, as Steam handles translating the PS4 input to XInput, which Unreal Engine supports. If you're not playing on Steam, try a third party like DS4Windows to achieve the same thing Steam does out of the box.
Certain wireless audio devices, audio interfaces, or third party audio enhancements seem to not play nice with our version of Unreal Engine, like Steelseries Sonar. Try disabling those and see if that fixes the issue. We are still collecting data about this bug.
If you're playing the Steam Build, try Verify Integrity of Game Files on Steam, then re-applying the R18 patch if you have one installed. If using a Launcher / Denpasoft / Sekai Project build, try redownloading the game, the download might have corrupted in transit.
This is a known bug, and one that is being worked on. Unfortunately, this bug is difficult to repro consistently so the fix has been ongoing for a while. To clear the visual artifacts, turn shadows to POTATO and back to your preferred setting. Sorry about how long this is taking to fix.
Try restarting the launcher, and if that doesn't work, “Uninstall Current Channel” in Settings and reinstalling. Your saves will be retained.
On Windows, save files will be stored in C:\Users\<YOURUSERNAME>\AppData\Local\MagicalGirlDF . You can get there faster by pressing Windows Key + R and typing in %localappdata%
our Discord is the quickest way to reach us quickly directly.