Terrible volume. It's very low

So I just bought an LG G5 from eBay. Great phone but the audio volume for headphones and Bluetooth is very low on max compared to my old Galaxy s4.

There is apps to make it louder but they all suck in my opinion.

Is it just my LG G5 or are they all like this? Is there a way to make this phone sound as good as my old Galaxy?

Is rooting recommended? I don't know how to do it.