Spectral sequence of SN 2020xga (panel a) from −9 to +37.8 rest-frame days and SN 2022xgc (panel b) from −0.7 to +92.1 g-band rest-frame days. An offset in flux was applied for illustration purposes. The spectroscopic measurements have undergone absolute flux calibration to align with the photometric data. The spectra are corrected for MW extinction and are smoothed using a Savitzky-Golay filter. The original data are presented in lighter colors. Regions of strong atmospheric absorption are blue-shaded.