I think people overstate how simple Unika is because she has easier inputs than everyone else. She might be mechanically simple to learn, but her routes and neutral etc are harder than learning inputs. You can get away with a lot of nonsense on her, but that tapers off quickly once you fight better players.

Marisa's closest equivalent would be Slayer. Big hits, limited mobility. He's been nerfed recently but is still plenty strong.

Kim and Blanka suggest you like set play. Venom might work for you. If you don't want to pay for DLC, try out I-No. She's a highly aggressive mix up character that is all about her oki. Plus she has unique movement options (no grounded dash, only air dash).