Correcting my post from above. I'll link a thread that already has been posted about this
issue:https://forum.deadbydaylight.com/en/discussion/297294/brightness-after-5-4-0 I suggest reading the comments, it seems like someone found a way to resolve their issue.
For the future, lease bugs you encounter generally
here:https://forum.deadbydaylight.com/en/categories/bugs (And we also don't have a bug report section on Steam)
For any tech issues, do so here:
https://forum.deadbydaylight.com/en/categories/technical-issues