Advice on complex background removal?

[denzjos]

Maybe you can select part of the complex by using :
G'Mic-Qt / Repair / Local Similarity Mask
I've used following parameters :
center x 43.30 y 46,92 (you can move the white dot around by using the mouse)
keep 74
reject 88
channels Lightness
Steps 100

part of the job is done :