Hello!
The question with an ID of 1073 (In “Clash Royale” what is Arena 4 called?) appears to have an incorrect answer.
The current 4th arena is known as ‘Spell Valley’. When Clash Royale was released, the current answer was correct, however in the years since they’ve released a significant number of new arenas and changed up the ordering. It appears this specific change was made in 2022.
Here’s an in-game screenshot taken today:
Here’s a web link corroborating the information; Arenas | Clash Royale Wiki | Fandom