There are only a few things you can take into consideration with the anime, and those are the things that happen offscreen in the manga, so Toei takes liberties
Changing stuff that happen onscreen in the manga (like Sanji vs King, Zoro cutting a cliff so Big Mom could fall, Big Mom hitting the sea, etc) is unnecessary imo, but i admit sometimes they do a far better job than Oda
Sometimes the anime can make more clear stuff that actually happens in the manga, but that aren't actually clear for the readers to understand due to Oda's laziness, such as Zoro trading blows with Kaido before hitting him with Asura, that happened in the manga as the sfx tells us
So the anime can improve a lot of things in that regard