Powers & Abilities - Who used haki and who not?

We know prior to the timeskip we did not see hardening or CoA at all. CoO at least was hinted at (breath of all things, skypea, all the sensing/feeling

Haki/Haoshoku Haki, One Piece Wiki

No wonder Bb wanted boa's fruit, not even haki can negate it's powers : r/OnePiecePowerScaling

One Piece: What is Haki? - All Forms of Haki Explained - FandomWire

Completely unrelated but haki seems to give less/no resistance to awakened devil fruit abilities : r/OnePiece

Haki, All Worlds Alliance Wiki

If armament Haki is used to negate devil fruit powers, how come Luffy is able to use his rubber powers along with Haki as Haki should negate his devil fruit power?

One Piece: What Devil Fruit Powers Can Haki Beat?

Can conquerors haki improve when you are not fighting seriously with someone? - Quora

Limitations of Armament-Haki : r/OnePiece