World Editor Crashing

Ive made a million maps with the old world editor. It worked and was intuitive. I haven't made a map since that editor was removed because of how buggy the new one is. Its been years and I still cannot import a terrain without some sort of bug or crash. Even when I manage to import a terrain, all materials vanish and clicking + to re add them crashes the game. I cannot even write a post about a specific crash because everything I try to use the world editor crashes the game.

How are you people creating maps??