For those who think Kaido got massively stronger after his 40's

Kaido didn't get magically stronger from sitting in his castle doing nothing, Oden would still give him a difficult fight. : r/OnePiecePowerScaling

Debunking the “kaido was massively fatigued” take : r/OnePiecePowerScaling

Kaidou, One Piece Wiki

Hot take of the day: Big Mom is a way better emperor than Kaido : r/MemePiece

All feats says how absurdly strong Yamato is, and that she is Low Yonkou level. : r/OnePiecePowerScaling

Powers & Abilities - Oden and Kaido surpassed Whitbeard and Roger, full analysis

I'm calling it. Roger easily defeated Kaido here. That's why Kaido put him in his top 5 list : r/OnePiecePowerScaling

Yonko Kaido vs Yujiro Hanma, does Baki's father stands a chance against the (One Piece) World's Strongest Creature? - Quora

Oden vs IJ Sanji - Battles - Comic Vine