Left: Comparison of the goodness-of-fit on the observational space: the difference between the RMSEs of the resimulated Phoenix spectra and the RMSEs of the modified template spectra. Right panel: Number of samples where the corresponding method has a better fit (i.e. a smaller RMSE) to the original input spectrum. If the difference between the RMSEs is within 0.3 × 10⁻⁵, they are classified as “similar”. These cases are indicated by the purple shaded area in the left panel and a purple bar in the right panel. We use the Clean group in the upper panels and the Uncertain group in the lower panels.