Using the New Default+ texture pack with Broken Paths did in fact allow the game to load up, but seeing certain CIT textures such as the "Piglin Brute Netherite Helmet" (yes its specific but its how it crashed the first time).

The error log is as follows:

20:49:07.744
net.minecraft.class_310
Render thread
Reported exception thrown!
net.minecraft.class_148: Registering texture
at net.minecraft.class_757.method_3192(class_757.java:883)
at net.minecraft.class_310.method_1523(class_310.java:1112)
at net.minecraft.class_310.method_1514(class_310.java:728)
at net.minecraft.client.main.Main.main(Main.java:217)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:234)
at net.fabricmc.loader.launch.knot.Knot.launch(Knot.java:153)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:28)
Caused by: net.minecraft.class_151: Non [a-z0-9/._-] character in path of location: minecraft:optifine/cit/models/new_default+_dungeons/armor_models/piglin_brute_armor_1.png.mcmeta
at net.minecraft.class_2960.(class_2960.java:41)
at net.minecraft.class_2960.(class_2960.java:50)
at net.minecraft.class_3294.method_14473(class_3294.java:170)
at net.minecraft.class_3294.method_14486(class_3294.java:50)
at net.minecraft.class_3304.method_14486(class_3304.java:62)
at net.minecraft.class_1049$class_4006.method_18156(class_1049.java:81)
at net.minecraft.class_1049.method_18153(class_1049.java:57)
at net.minecraft.class_1049.method_4625(class_1049.java:28)
at net.minecraft.class_1060.method_24303(class_1060.java:96)
at net.minecraft.class_1060.method_4616(class_1060.java:68)
at net.minecraft.class_1060.method_4619(class_1060.java:118)
at net.minecraft.class_4668$class_4683.method_23563(class_4668.java:238)
at net.minecraft.class_4668.method_23516(class_4668.java:36)
at com.google.common.collect.ImmutableList.forEach(ImmutableList.java:408)
at net.minecraft.class_1921$class_4687.method_23595(class_1921.java:929)
at net.minecraft.class_4668.method_23516(class_4668.java:36)
at net.minecraft.class_1921.method_23012(class_1921.java:727)
at net.minecraft.class_4597$class_4598.method_22994(class_4597.java:96)
at net.minecraft.class_4597$class_4598.method_24213(class_4597.java:75)
at java.base/java.util.Optional.ifPresent(Optional.java:178)
at net.minecraft.class_4597$class_4598.method_22993(class_4597.java:72)
at net.minecraft.class_490.method_2486(class_490.java:155)
at net.minecraft.class_481.method_2389(class_481.java:779)
at net.minecraft.class_465.method_25394(class_465.java:101)
at net.minecraft.class_485.method_25394(class_485.java:43)
at net.minecraft.class_481.method_25394(class_481.java:690)
at net.minecraft.class_757.method_3192(class_757.java:874)
... 10 more

Are you sure broken paths is enabled? also send the entire logs file please

I'll reopen the issue once more context is provided. New Default+ was tested already in the past without crashing on a clean setup.

@MeikelLP dont use other people's issues for this please. You need to enable Broken Paths in the config to fix this or contact the pack author to fix their pack.