Dabura learned rct, technique reversal, domain expansion. From NOWHERE. If he had been fighting like gojo and fogured out that red is just the reversal of blue than i can get it. But at no point did mahoraga show him what a domain was, what rct was, nor what technique reversal is
All I will say is dabura was learning stuff that's pretty doable for a sorcerer at that lvl,
Meanwhile sukuna was doing stuff that's stated to be outright impossible.