2010 Airbender? Like seriously, just about everything about it was poorly done. Writing, action scenes and more. Hard to say to what I'd do differently other than maybe consider not making the movie altogether. Some things are just not meant to be made into live action.
Some movies are just meant to stay trash aka most DCEU movies.
I'd make Superman III and IV less milking and out of place comedy and more serious but light hearted like 1 and 2.
Now that I think about it, Superman III and IV and DCEU are polar opposites. both are trash writing of course and ruin their characters but ones deliberately tries to be a joke and the other tries to be so serious and dark/edgy that it becomes a trash movie.
Then I'd redo Spider-Man Homecoming and instead use it to integrate Tobey Spider-Man as an older Spider-Man, who retired during the MCU and is off the radar and that's why you don't hear about him or his exploits. But it is a pipe dream of course.