You are asking for a miracle
I understand what you mean. But its extremely difficult - I am not concerned about fans and what they say. The problem will always be balancing characters. As I said characters from same franchise are tricky but make sense. However I have my doubts that balancing them in movies is easier than comics, in Aquaman movie you had instances in which she overshadows him and actually saves his butt more than once. Ok Momoa emerges ultimately.
With characters of different franchises it will depend on who is the character. If Diana dates Hal Jordan its one thing if its Bruce Wayne the clout of the later is big. Batman or Superman's personality and even their presence steals the show even with the best intentions of actors, directors and writers.