I’m starting on a card game project and I thought I’d ask this first before I’m way too deep into the project.
It’s all based on preference. Some people prefer to use UI, which can auto-scale to screen size, while others prefer to scale it themselves. UI elements require RectTransform, where real space games use transform. Real space is easier to animate features.
Personal preference would be to create the game in real space, and manually scale the game to screen size. Because then you can control the scaling and animations won’t go crazy.