Help with Deckbuilding UK

I need help with deckbuilding :(

I’m completely brand new and out of my element. I usually play MTG so have no idea what’s going on but I want to join my friends to a tournament in Cardiff soon.

I want a cute yet strong deck, like cat girls or wistella? I don’t know what they’re called. Can someone recommend me something? I don’t want a deck with those complicated dragons and mechas 😔