All Unreal Engine made games only have sound at the logo, but not in game. Solution?

Fortnite has no sound at all. Other games using the Unreal Engine (Steam games like The Invisible Hours, Sprint Vector, or Rad Rodgers) all have the same issue.

I have tried reinstalling my Realtek sound drivers (currently v10.0.17134.1 from 4/11/2018 from Microsoft), but it didn’t fix anything. Up until about 4 months ago, Fortnite (and my other games) had sound. All other non-Unreal games work flawlessly.

I’ve tried using headphones and other speakers, and have not had any luck. Any suggestions?