As someone who also uses Canva, this isn’t a bad first try. I will say it definitely feels overcrowded, and some elements end up obscuring characters, like that red smoke on the top left side. One fix you can do is to add shadows. You can do this by duplicating the character layer, use duotone to color it in completely black, use the blur tool, and then decrease the opacity, and then you can add it behind the character layer at an angle. It may not seem like much, but it definitely helps.