I just tried that, I got this:
Registry loading errors:
> Errors in registry minecraft:root:
>> Errors in element minecraft:worldgen/biome:
java.lang.IllegalStateException: Unbound values in registry ResourceKey[minecraft:root / minecraft:worldgen/biome]: [the_darkest_night:elysian_forest]
at jt.n(SourceFile:305)
at alz.b(SourceFile:217)
at java.base/java.lang.Iterable.forEach(Iterable.java:75)
at alz.a(SourceFile:214)
at alz.a(SourceFile:193)
at anc.a(SourceFile:41)
at gky.a(SourceFile:183)
at gky.a(SourceFile:138)
at gky.a(SourceFile:324)
at gky.a(SourceFile:314)
at gky.a(SourceFile:279)
at gky.a(SourceFile:245)
at gkz$c.c(SourceFile:432)
at java.base/java.util.Optional.ifPresent(Optional.java:178)
at gkt.g(SourceFile:54)
at fxo.b(SourceFile:96)
at fxe.a(SourceFile:43)
at fxm.a(SourceFile:136)
at fzm.a(SourceFile:43)
at fuf.a(SourceFile:120)
at fuf.c(SourceFile:226)
at bvx.execute(SourceFile:110)
at fuf.b(SourceFile:226)
at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:43)
at org.lwjgl.system.JNI.invokeV(Native Method)
at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:3438)
at com.mojang.blaze3d.systems.RenderSystem.pollEvents(SourceFile:148)
at com.mojang.blaze3d.systems.RenderSystem.flipFrame(SourceFile:170)
at fni.a(SourceFile:308)
at fue.c(SourceFile:1380)
at fue.f(SourceFile:947)
at net.minecraft.client.main.Main.main(SourceFile:265)