How to make a non-monotone background transparent?

Question

Adobe Photoshop

For example, I have a picture.

I need to remove the brown background and leave the full picture, but it doesn't work.
What I tried - set the RGB mode, then the selection and the color range, selected the background color with an eyedropper, set the spread to 50 (I tried it up to 100, it’s not the same anymore), then I erased the background with the background eraser.
As a result, this is what I got

. In general, it’s not at all ...

Tell me to make the background transparent in my situation?