This achievement requires unlocking all 144 upgrades (48 upgrades per category) from the Soul, Technique and Body categories within the Abilities tab, using Exp. You do not have to unlock any upgrades from the Dragon category to obtain this achievement.
Exp is earned very easily and regularly within Yakuka Kiwami from just playing the game (completing the story missions, doing substories, fighting Majima etc.)
EDIT: make sure you close and re-open the Abilities tab once you have purchased the last upgrade as this achievement can be glitchy and refuse to pop.