Same, on windows I have had changed the front levels of the speakers to work in the range 0-25%. But I never know how the hell to reach that dialog in an easy way. I couldn’t explain how I did it.
This link explains something else but the screen captures are similar. But for “front” you have to scroll down. https://www.abyssmedia.com/isound7/how-to-hear-line-in.shtml
Socrates would be proud.