This seems to happen sometimes when a biome has a certain "offset" parameter number. Here's what I got of the crash log:

---- Minecraft Crash Report -------- Minecraft Crash Report ----// Daisy, daisy...
Time: 6/08/20 17:44Description: Exception in server tick loop
java.lang.IllegalStateException: Unregistered dimension type: cha@90d4173 at net.minecraft.server.MinecraftServer.b(SourceFile:365) at net.minecraft.server.MinecraftServer$$Lambda$4144/982807943.get(Unknown Source) at java.util.Optional.orElseThrow(Optional.java:290) at net.minecraft.server.MinecraftServer.a(SourceFile:365) at net.minecraft.server.MinecraftServer.l_(SourceFile:332) at emy.d(SourceFile:68) at net.minecraft.server.MinecraftServer.w(SourceFile:644) at net.minecraft.server.MinecraftServer.a(SourceFile:254) at net.minecraft.server.MinecraftServer$$Lambda$4136/1264078907.run(Unknown Source) at java.lang.Thread.run(Thread.java:745)

A detailed walkthrough of the error, its code path and all known details is as follows:---------------------------------------------------------------------------------------
– System Details --Details: Minecraft Version: 1.16.2 Pre-release 2 Minecraft Version ID: 1.16.2-pre2 Operating System: Windows 10 (amd64) version 10.0 Java Version: 1.8.0_51, Oracle Corporation Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation Memory: 1463532944 bytes (1395 MB) / 2147483648 bytes (2048 MB) up to 2147483648 bytes (2048 MB) CPUs: 4 JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M Player Count: 0 / 8; [] Data Packs: vanilla, file/datapack_biomas Type: Integrated Server (map_client.txt) Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.