Output channels

Hello. I would like to know if output channels are independent or not. They are called 1/L and 2/R, but in Windows they are seen like R and L, a single stereo output, not output 1 and output 2. That’s because I want to EQ speakers and subwoofer separately using REW. And even if I split the outputs R and L, and EQ them, they are still mono lines, so there’s not right and left anymore. When sounds come from right or left, both speakers play it. So this way I lose in quality sound etc.
Any solutions or should I go for a 2x4 interface? Thanks.

Output one is left, output two is right. Very clear. Or not?

Yes, maybe I explained bad my request. In windows they are seen “Line out”, a single stereo one. Not 2 separate lines out. I wanted to plug speakers to 1st output and subwoofer to 2nd output, to EQ them separately. But I think they are 2 mono outputs.

Output one is left (or mono 1) output two is right (or mono 2).
A stereo line out contains a left and a right signal, two channels.

No. You lose the stereo information.

Didn’t I explain it, not good enough?
Try another hobby, please… Maybe knitting?