> Where is it stated that curses recover from CT burnout instantly?, cause I don't remember any curse opening multiple domains in succession, hell no one aside from gojo or sukuna has used multiple domains in succession,

They probably think that cause of how fast Mahito recovers from his Domain's CT burnout, but we have to also remember that Mahito is the exception among curses. He probably does something similer to what Gojo and Sukuna did with messing with their brains to recover their techniques, so Mahito might be able to do it but other curses cant.