Nintendo has announced what it describes as the final update to Super Mario Maker 2, and it comes with a huge new feature: a World Maker mode that lets you design a map and string multiple courses together, Super Mario World-style.
https://www.theverge.com/2020/4/20/21229029/super-mario-maker-2-world-maker-mode-final-update
https://www.theverge.com/2020/4/20/21229029/super-mario-maker-2-world-maker-mode-final-update