So.... after 3 hours of debugging 250 mods, your mod prevented world creation in a server instance.
I did this one by one, disabling mod after mod, and it came down to Immersive Weapons. There is no log indicating why, but there is a crash error I can provide .

Latest Immersive Weapon version
1.18
Modloader 38.0.17

[20:24:49] [main/FATAL]: Failed to start the minecraft server
java.lang.RuntimeException: Missing referenced custom/removed registry entry for registry ResourceKey[minecraft:root / minecraft:worldgen/biome] named minecraft:overworld
at com.mojang.serialization.DataResult.lambda$getOrThrow$4(DataResult.java:100) ~[datafixerupper-4.0.26.jar%2329!:?]
at com.mojang.datafixers.util.Either$Right.map(Either.java:99) ~[datafixerupper-4.0.26.jar%2329!:?]
at com.mojang.serialization.DataResult.getOrThrow(DataResult.java:93) ~[datafixerupper-4.0.26.jar%2329!:?]
at net.minecraft.server.Main.main(Main.java:175) ~[server-1.18-20211130.085255-srg.jar%23265!:?]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?]
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?]
at net.minecraftforge.fml.loading.targets.CommonServerLaunchHandler.lambda$launchService$0(CommonServerLaunchHandler.java:46) ~[fmlloader-1.18-38.0.17.jar%2323!:?]
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-9.0.7.jar%235!:?]
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:53) [modlauncher-9.0.7.jar%235!:?]
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:71) [modlauncher-9.0.7.jar%235!:?]
at cpw.mods.modlauncher.Launcher.run(Launcher.java:106) [modlauncher-9.0.7.jar%235!:?]
at cpw.mods.modlauncher.Launcher.main(Launcher.java:77) [modlauncher-9.0.7.jar%235!:?]
at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26) [modlauncher-9.0.7.jar%235!:?]
at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23) [modlauncher-9.0.7.jar%235!:?]
at cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:90) [bootstraplauncher-0.1.17.jar:?]

I'll take a close look at the issue soon. But just from glancing at the log snippet, it seems like it's a worldgen problem. Which is odd, because I thought I had disabled all of it for the 1.18 beta releases (due to issues in the Forge API).

Found the problem. Part of the datapack for working with custom dimensions wasn't fully disabled, and so it would fail since the entries weren't being registered. I'll have a new beta release out soon.

Should be fixed as of the latest 1.18.1-beta3 release. Let me know if anything else breaks.

will try it out now, thank you.