Sorry for bad English (If it's bad) :(

I just intalled Fabric ModLoader for BetterNether, and it didn't work.

I am using 1.16.1 Fabric ModLoader

I have the following mods in my Mods folder:
better-nether-3.2.5.jar (crashing mod)
fabric-api-0.14.1+build.372-1.16.jar
modmenu-1.12.2+build.17.jar

I've tried:
older versions of mod
deleting all configs
Updating java
re-installing mod and fabric api
other versions of fabric modloader

the Crash Report is HERE:

---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!

Time: 09.07.2020 10:11
Description: Initializing game

java.lang.RuntimeException: Could not execute entrypoint stage 'main' due to errors, provided by 'betternether'!
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:53)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:36)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient.start(EntrypointClient.java:32)
at net.minecraft.class_310.(class_310.java:425)
at net.minecraft.client.main.Main.main(Main.java:177)
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.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:192)
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:140)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:26)
Caused by: java.lang.ExceptionInInitializerError
at paulevs.betternether.BetterNether.onInitialize(BetterNether.java:30)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient$$Lambda$2156/1424091303.accept(Unknown Source)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:50)
... 11 more
Caused by: java.lang.IllegalArgumentException: Block{minecraft:air} has property: shape with invalidly named value: mıddle
at net.minecraft.class_2689$class_2690.method_11669(class_2689.java:145)
at net.minecraft.class_2689$class_2690.method_11667(class_2689.java:125)
at paulevs.betternether.blocks.BlockStalagnate.method_9515(BlockStalagnate.java:30)
at net.minecraft.class_2248.(class_2248.java:183)
at paulevs.betternether.blocks.BlockBase.(BlockBase.java:19)
at paulevs.betternether.blocks.BlockBaseNotFull.(BlockBaseNotFull.java:13)
at paulevs.betternether.blocks.BlockStalagnateStem.(BlockStalagnateStem.java:19)
at paulevs.betternether.blocks.BlockStalagnate.(BlockStalagnate.java:21)
at paulevs.betternether.registry.BlocksRegistry.(BlocksRegistry.java:27)
... 14 more

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Thread: Render thread
Stacktrace:
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:53)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:36)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient.start(EntrypointClient.java:32)
at net.minecraft.class_310.(class_310.java:425)

-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.main.Main.main(Main.java:177)
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.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:192)
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:140)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:26)

-- System Details --
Details:
Minecraft Version: 1.16.1
Minecraft Version ID: 1.16.1
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: 2305761440 bytes (2198 MB) / 2684354560 bytes (2560 MB) up to 4294967296 bytes (4096 MB)
CPUs: 12
JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx4G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
Fabric Mods:
betternether: Better Nether 3.2.5
fabric: Fabric API 0.14.1+build.372-1.16
fabric-api-base: Fabric API Base 0.1.3+12a8474c02
fabric-biomes-v1: Fabric Biomes (v1) 0.2.7+059ea86602
fabric-blockrenderlayer-v1: Fabric BlockRenderLayer Registration (v1) 1.1.4+c6a8ea8902
fabric-command-api-v1: Fabric Command API (v1) 1.0.8+5ce5339802
fabric-commands-v0: Fabric Commands (v0) 0.2.0+52d3083602
fabric-containers-v0: Fabric Containers (v0) 0.1.8+045df74f02
fabric-content-registries-v0: Fabric Content Registries (v0) 0.1.9+059ea86602
fabric-crash-report-info-v1: Fabric Crash Report Info (v1) 0.1.2+b7f9825d02
fabric-dimensions-v1: fabric-dimensions-v1 1.0.0+a71b305302
fabric-events-interaction-v0: Fabric Events Interaction (v0) 0.3.3+7066030f02
fabric-events-lifecycle-v0: Fabric Events Lifecycle (v0) 0.2.0+16acbe5b02
fabric-item-api-v1: Fabric Item API (v1) 1.0.0+16acbe5b02
fabric-item-groups-v0: Fabric Item Groups (v0) 0.2.0+438f963602
fabric-key-binding-api-v1: Fabric Key Binding API (v1) 1.0.0+e16a977402
fabric-keybindings-v0: Fabric Key Bindings (v0) 0.2.0+3fa9f7c502
fabric-lifecycle-events-v1: Fabric Lifecycle Events (v1) 1.0.0+b0993bc102
fabric-loot-tables-v1: Fabric Loot Tables (v1) 0.1.10+059ea86602
fabric-mining-levels-v0: Fabric Mining Levels (v0) 0.1.2+b764ce9902
fabric-models-v0: Fabric Models (v0) 0.1.0+dfdb52d602
fabric-networking-blockentity-v0: Fabric Networking Block Entity (v0) 0.2.5+b50ffc7b02
fabric-networking-v0: Fabric Networking (v0) 0.1.10+e00ecb5f02
fabric-object-builder-api-v1: Fabric Object Builder API (v1) 1.5.5+e00ecb5f02
fabric-object-builders-v0: Fabric Object Builders (v0) 0.6.0+da175ad602
fabric-particles-v1: fabric-particles-v1 0.2.1+0a6f2a7002
fabric-registry-sync-v0: Fabric Registry Sync (v0) 0.3.8+7dba2d6c02
fabric-renderer-api-v1: Fabric Renderer API (v1) 0.2.13+eae12eb802
fabric-renderer-indigo: Fabric Renderer - Indigo 0.3.2+4d66bed502
fabric-renderer-registries-v1: Fabric Renderer Registries (v1) 2.0.1+5a0f9a6002
fabric-rendering-data-attachment-v1: Fabric Rendering Data Attachment (v1) 0.1.3+b7f9825d02
fabric-rendering-fluids-v1: Fabric Rendering Fluids (v1) 0.1.8+b7084faa02
fabric-rendering-v0: Fabric Rendering (v0) 1.1.0+5341049002
fabric-rendering-v1: Fabric Rendering (v1) 1.1.2+346247d702
fabric-resource-loader-v0: Fabric Resource Loader (v0) 0.2.6+f41e209802
fabric-screen-handler-api-v1: Fabric Screen Handler API (v1) 1.0.1+f362c86e02
fabric-tag-extensions-v0: Fabric Tag Extensions (v0) 0.2.7+a4c57d8e02
fabric-textures-v0: Fabric Textures (v0) 1.0.4+eae12eb802
fabric-tool-attribute-api-v1: Fabric Tool Attribute API (v1) 1.1.4+5794386e02
fabricloader: Fabric Loader 0.8.8+build.202
minecraft: Minecraft 1.16.1
modmenu: Mod Menu 1.12.2+build.17
Launched Version: fabric-loader-0.8.8+build.202-1.16.1
Backend library: LWJGL version 3.2.2 build 10
Backend API: NO CONTEXT
GL Caps:
Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'fabric'
Type: Client (map_client.txt)
CPU:

This issue appears to be with the BetterNether mod. This is for Fabric itself and they cannot fix bugs for other mods.

You might try posting this here: https://github.com/paulevsGitch/BetterNether/issues

They will likely be able to fix it better than Fabric can.

Thanks. :)