Distribution of Ė_K,out as a function of L_Bol for different types of outflows. The dotted, dot-dashed, and dashed lines indicate the thresholds of 0.1, 1, and 10 percent, respectively. The dark and light green star symbols denote the EHVO outflow of SMSS J2157 as reported in this paper by adopting N_H^C_fmin and N_H^C_fmax, respectively, while the empty star represents Ė_K,out obtained by adopting N_H = 10²² cm⁻² and R_EHVO = 100 pc, values generally derived using VHP outflows and excited states, respectively (see Sect. 5 for a detailed discussion). Other symbols denote the parameters of X-ray (blue triangles), ionized (red crosses), and BAL outflow (orange stars) reported by Fiore et al. (2017), SUBWAYS X-ray UFO from Gianolli et al. (2024), BAL reported by Miller et al. (2020) (right-pointing triangles), and EHVO from Vietri et al. (2022) (blue star).