DC literally had the entire gameplan laid out before them on how to translate their comics into a cinematic universe and have it be amazing and make shitloads of dosh. All they had to do what copy what Marvel did, thats it! They fucked it up! How did they fuck it up so badly?
The whole thing about Marvel was that they released all these individual movies to introduce characters and they took the time to tell a unique story for each hero in their own movie or even multiple movies, so that when Avengers finally came around it was like, all those movies culminated to that moment where theyre together on the screen. Theres a feeling like, "all these heroes youve come to know and love over a long time, are now teaming up together in one big movie" and that carries a sort of weight when you build everything properly over time like Marvel did.
DC was and is simply just all over the place. DC wanted to skip the buildup and jump right into the Avengers level hype and media and money. But you dont get that without doing the slow buildup and gradual worldbuilding, without the years of establishing plot and setting. They kinda just threw you in there and gave it to you all at once, which doesnt make it feel like some big event that was built up to, it kinda just exists. They arent established parts coming together into something greater than they were, its just "the Justice League."
and that brings me to my main point, DC is never going to be like Marvel. They fucked it up so hard its never gonna be what it could have been. 100s of batman movies, 100s of superman movies, reboots of everything out the ass, multiple versions of movies, rebooting again after you already established a timeline. You would have to erase every DC movie post Dark Knight from existence and everybody's memory and start fresh.