Vimshottari dasha-antardasha are essentially progressions of the natal moon in cycles of 120 degrees = 120 years (but not in a simplistic one degree per year rate), which essentially formed an important basis of Krishnamurthi Paddhati (K.P.) and led to the elaborations in that system which departed from standard and traditional jyotish and used Placidian cusps and cusps taken as beginning of house (Raphael's ephemeris and tables of houses were the standardized books available for those who did not rely on the panchangas and ponjikaas which varied widely from one another and so on.
So I can kind of get why you chose to use the term 'activation' (progressed moon knocking at the door of the ruler of the nakshatra as it arrives at that nakshatra? So someone born with moon in bharani (venus) progressing to Krittika (subject to preferred ayanamsha) and activating or getting attuned to Sun in the specific natal chart...!
Proportionately, the nakshatras are sub-divided in subs in KP and each sub is ruled by the planets in the order of nakshatras (ketu, venus, sun, moon... etc) starting with the first antardasha ruled by the Nakshatra lord that is welcoming progressed moon and then the next, then the next.
Those who believe that planets make everything happen might be happy with the term "activating", but those who visualize astrological planets as karmic indicators might feel more comfortable with the term: indicating...!
But, to each his own universe and perceptual reality in the quantum reality of astrology...?