"We call this awakening. Your mind and body are finally able to harness the potential of your ability" - Kaido. Never about some death thing. Oda can use for metaphor or something but it never said to be a requirement. Chopper is an obvious example. Pre-ts neither his body nor his mind were strong enough to use it. He need rumble balls to use any zoan form and he can not control monster point. After ts his body is strong enough to use zoan form without rumble and his mind can surpass the will of his zoan.
Impel down beast were awakened
Lucci and kaku figured out awakening
None of the beast pirates were awakened
Luffy only awakened after dying
Kaido is obsessed with death completing a person and suicide is a hobby for him