As far as sound and device management goes, I'd recommend getting Voicemeeter. It's a program that allows you to manage how loud or quiet your levels are in one place, and lets you choose more input/output devices. It's really great when you learn how to use it.
This really does sound like a problem with Unreal if you have gone through windows to check levels. What I'd recommend you do is go into your device properties here:
(You can do this without Voicemeeter, I have it so it gives me more recording options)
And when you're there, navigate the tabs to "Levels"
Fiddle with the Gain a bit. You might want to turn it down, if you're having loudness problems.
If that doesn't fix, let me know what microphone you have.