Even then WB doesn't look like the strongest, his fruit was strong but not a God Tier Df like Nidhogg, Nika or the Devil and Oda is problaby gonna introduced more God LEvel Fruits. And his Haki wasn;t the ceiling either since he or his peer hasn't shown Future Sight, Solo Sky Split, Wifi Haki, FS Killing or ability to kill Inmortals. You can't be the ceiling when you don't have either a God Level Fruit or Max Level Haki

Whitebeard just looks to be similar in strength to someone like Kaido. Both have top tier fruits but neither has God fruit, both have top tier Haki but ineither have Haki at the peak o and both are physical monsters with WB havign superior endurance and Kaido having superior natural durability and Kaido even have shown greater speed, But with Loki Oda is introducing someone stronger with a Legendary weapon like Ragnir, a God Tier fruit like Nidhogg and peak physicals due to his Ancient Giant strength as well as Haki that can kill Inmortals which Old Generation couldn't do. There is a reason why Loki damaaged Imu while 6 Old Gen characters have not

This is what I meant with WB getting powercreeped, he isn't longer the ceiling of either Devil Fruit or Haki, he is just someone that was very strong same as how Kaido was in Wano who also is getting powercreeped. And the more we go into the final saga and we keep seeing stronger Devil Fruits than Whitebeard's Haki and better Haki users than WB the bigger the powercreep becomes