This issue has been fixed after messaging the mod owner and sorting it out with them. However for some modpacks, if this mod is added ensure that all Curios slots are enabled. If any are disabled it will give a Ticking Player crash with the details 'Java.lang.RuntimeException: Slot 0 not in valid range - [0,0).

You can edit the config files of Curios in the saves of your worlds to ensure none are set to 'Size=0' which disables them.

crash-2022-04-12_14.36.54-server.txt

So I did that. Now the world technically doesn't crash, just freezes upon world loading screen. No crash report generated, but I found this in the log:

Encountered an unexpected exception
com.electronwill.nightconfig.core.conversion.InvalidValueException: Unexpected element of type class java.lang.String in collection of objects
at com.electronwill.nightconfig.core.conversion.ObjectConverter.convertConfigsToObject(ObjectConverter.java:417)
at com.electronwill.nightconfig.core.conversion.ObjectConverter.convertToObject(ObjectConverter.java:276)
at com.electronwill.nightconfig.core.conversion.ObjectConverter.toObject(ObjectConverter.java:101)
at com.electronwill.nightconfig.core.conversion.ObjectConverter.toObject(ObjectConverter.java:114)
at top.theillusivec4.curios.common.CuriosConfig.transformCurios(CuriosConfig.java:44)
at top.theillusivec4.curios.Curios.config(Curios.java:176)
at top.theillusivec4.curios.Curios$$Lambda$5888/2111215208.accept(Unknown Source)
at net.minecraftforge.eventbus.EventBus.doCastFilter(EventBus.java:247)
at net.minecraftforge.eventbus.EventBus.lambda$addListener$11(EventBus.java:239)
at net.minecraftforge.eventbus.EventBus$$Lambda$2846/652485732.invoke(Unknown Source)
at net.minecraftforge.eventbus.EventBus$$Lambda$3206/1265616405.invoke(Unknown Source)
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:302)
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:283)
at net.minecraftforge.fml.javafmlmod.FMLModContainer$$Lambda$2998/1331735601.accept(Unknown Source)
at net.minecraftforge.fml.ModContainer.lambda$dispatchConfigEvent$7(ModContainer.java:138)
at net.minecraftforge.fml.ModContainer$$Lambda$45462/163976795.accept(Unknown Source)
at java.util.Optional.ifPresent(Optional.java:159)
at net.minecraftforge.fml.ModContainer.dispatchConfigEvent(ModContainer.java:138)
at net.minecraftforge.fml.config.ModConfig.fireEvent(ModConfig.java:76)
at net.minecraftforge.fml.config.ConfigTracker.openConfig(ConfigTracker.java:92)
at net.minecraftforge.fml.config.ConfigTracker.lambda$loadConfigs$1(ConfigTracker.java:69)
at net.minecraftforge.fml.config.ConfigTracker$$Lambda$45442/1098994071.accept(Unknown Source)
at java.lang.Iterable.forEach(Iterable.java:75)
at java.util.Collections$SynchronizedCollection.forEach(Collections.java:2062)
at net.minecraftforge.fml.config.ConfigTracker.loadConfigs(ConfigTracker.java:69)
at net.minecraftforge.fml.server.ServerLifecycleHooks.handleServerAboutToStart(ServerLifecycleHooks.java:80)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at net.optifine.reflect.Reflector.callBoolean(Reflector.java:809)
at net.minecraft.server.integrated.IntegratedServer.func_71197_b(IntegratedServer.java:83)
at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:621)
at net.minecraft.server.MinecraftServer.func_240783_a_(MinecraftServer.java:232)
at net.minecraft.server.MinecraftServer$$Lambda$61468/932164267.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)

Any idea where the problem resides?

Sorry, I didn't see this till now. My bad.

Are you still getting this? Can you post your curios-server.toml or maybe it is your tags?

Not getting this crash now, but another one @ #300