If my opponent attacks with Dracozolt V's "Primeval Beak" attack, then on my turn I retreat the Pokemon that was attacked, can I attach Energy cards to that Pokemon?
Yes you may. The effect of Primeval Beak is removed when that Pokemon retreats, evolves, is switched to the Bench, etc.
Source: Evolving Skies FAQ; TPCi Rules Team (2021-08-26)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH7_58
SWSH7_58