Updated solar and stellar samples as shown in the lower panel of Fig. 1. Upper panel: Flaring of the 48 stars used in our analysis (highlighted in blue). Lower panel: Flaring activity of the 4 Sun-like stars transitioning between spot- and faculae-dominated stars. The flare energy of the only star in the sample that also shows a comparable rotation period (i.e., KIC 11599385) is highlighted by the dashed red line, which falls right within the reconstructions of the AD774/775 event.