May I ask why not let the monsters generate in the underground cave? I used spawner to increase the number of monsters, but the underground monsters are more than those on the ground, and the monsters on the ground are killed less and less. I added seesky to spawn: true No response QwQ (from Google Translate) (The picture below is my file: the first is spawner, the second is spawn)

That file is called spawn.txt though. That will not work. It has to be called spawn.json

I know, but I can't open two json files at the same time, so I'll copy the content of spawn.json into spawn.txt and take a screenshot for you to see. @McJty