Doesn't Batman, Superman, and Wonder Woman also know magic, so what? What you should be saying is how powerful they are with their magic compared to them.
Batman would probably be the first to die, and if rimuru can use gluttony on superman and copy his abilities it's kinda over since he'll be even stronger
I refuse DC Characters to loose, but I literally have no idea how powerful the other team is except being known for being the most powerful, well most and only Rimuru, Superman would destroy the others, it's only Rimuru who is a God-like figure.
Batman would have a hard time with any of them. Tanya the little blonde chick can make nukes with her prayer magic and has a lot of experience in aerial combat. Plus she’s really manipulative and an expert tactician. Think of her like a cute nazi girl that takes advantage of everything in her favor. The only person that has been able to stop her in her goal of living a care free life is a being that calls itself god. Batman’s plot armor can only do so much.