Can't say I see the problem. The original three movies give him one arc (maturing to be the king), then the events of Infinity War/Endgame upend his life and he comes out of it realizing he needs to do something else. They may have mashed the reset button a little too quickly after he became king, but one could argue that his realizing he couldn't be the leader that was needed and stepping aside for one that could was the mature decision, which would be a fair transition.