Wavelength k − z plane. The region between the two green lines corresponds to all possible scales probed by the LBG samples. The area above the dashed blue line indicates non-linear scales. Left: The red (black) distribution shows the 1-2σ weighted k − z map following n(z)² (n(z)W_κ(z), respectively) of the RF UNIONS-like selection from Payerne et al. (2025). Right: Same as the left plot, but for the UNIONS color-cut LBG selection.