If you have lot's of map files in your world file (in my case map_0.dat - map_400.dat) the game will crash when loading the world right before you're in the world. The more maps the wose it gets. World download: https://drive.google.com/file/d/1HE-WDnL7Cl44EK7oyhpbQFFvxaXj-tGc/view?usp=sharing

The Game didn't crash while i didn't have any maps in my world file (might be different reason though) and the version i played on doesn't have any mods. The World has been running on a Spigot and Paper server. The conversion is happening in the Vanilla game though

the game crashes once the world is loading screen is at 100%