but the interface has a noisy hiss by default regardless of what is plugged into the rest of the mixer and even if every knob is turned all the way down

This audio interface is really good for a starter

Instead buy a similarly priced and significantly better A/D interface, (Behringer UMC 202HD, UMC 404HD or Focusrite Scarlet 2i2) and eq. digitally

Really like interface via USB to my PC for recording

Easy to set up, lightweight, simple interface, compatible with Audacity software.

The USB interface for recording works great, however, when you use the USB to headphones button, it mutes the other inputs

It is providing a solid digital interface with good sound quality.

No need to find and spend another $100+ on a decent interface, because with the USB, it goes straight to the computer, just adjust your output audio setting on your computer (if it doesn’t automatically) and you

I'm in a small band and we needed a mixer we could use live as well as for home recordings

I use this primarily for OBS and works as it supposed to