Basically I wanted to try out the new customize feature in this snapshot, I saw some really interesting options, so I basically overdid a few of them including the full spawn size, height and tries on diamond ore, full dungeon count, lowest lava lake rarity and turned on lava ocean. I have been sitting 15 minutes or more trying to load this world, but the window is frozen in the "Loading world, Building terrain" screen (still responding, but unable to close). I was unable to force a crash because the game was frozen, so I don't have any crash logs, only way I closed minecraft was through task manager

I included the world in the attachments

Edit: I found that the problem occurs trying to load any world, even a default one. Also it seems this problem is only occurring for some people, so I have included some computer specs as well as the java verson in the environment