The existence of supermassive black holes (SMBHs) of 10^9 solar masses in quasars at cosmic ages of less than 700 Myr is an intriguing puzzle. How the seeds of these SMBHs have formed and grown so fast to become so large? Models of the compact seeds of the SMBHs observed at redshifts z > 6 propose in the context of dark matter cosmologies those seeds are formed by direct collapse in dark matter haloes. I will show that recent high-z ALMA and JWST observations are consistent with the astrophysical hypotheses in those models. Finally, integrating those recent theoretical and observational contexts, with past extensive studies of the environments of BH-jets in the local and distant universe, I will conclude that the relativistic jets and associated massive outflows from rapidly growing BHs at cosmic dawn must have enhanced the formation of Pop-III massive stars.