Here's one of my previous submissions with one version of level editing...(ascii text representation of a 2d level)
https://itch.io/jam/gamedevtv-halloween-jam-2025/rate/3960061
And here's another (even more difficult to consider level editing) that uses JSON pasted text... yikes.. 3d and a ton of JSON properties!
https://itch.io/jam/brackeys-14/rate/3842322