Crash log below:

---- Minecraft Crash Report ----
// I let you down. Sorry :(

Time: 2023-07-11 11:28:50
Description: Ticking entity

java.lang.IllegalAccessError: class net.minecraft.class_1309 tried to access private field net.minecraft.class_1297.field_6002 (net.minecraft.class_1309 and net.minecraft.class_1297 are in unnamed module of loader net.fabricmc.loader.impl.launch.knot.KnotClassLoader @57175e74)
at net.minecraft.class_1309.handler$bjp002$visuality$tick(class_1309.java:6655)
at net.minecraft.class_1309.method_5773(class_1309.java:2499)
at net.minecraft.class_1308.method_5773(class_1308.java:351)
at net.minecraft.class_3218.method_18762(class_3218.java:739)
at net.minecraft.class_1937.method_18472(class_1937.java:480)
at net.minecraft.class_3218.method_31420(class_3218.java:385)
at net.minecraft.class_5574.method_31791(class_5574.java:54)
at net.minecraft.class_3218.method_18765(class_3218.java:353)
at net.minecraft.server.MinecraftServer.method_3813(MinecraftServer.java:897)
at net.minecraft.server.MinecraftServer.method_3748(MinecraftServer.java:824)
at net.minecraft.class_1132.method_3748(class_1132.java:105)
at net.minecraft.server.MinecraftServer.method_29741(MinecraftServer.java:671)
at net.minecraft.server.MinecraftServer.method_29739(MinecraftServer.java:265)
at java.base/java.lang.Thread.run(Thread.java:833)

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

-- Head --
Thread: Server thread
Stacktrace:
at net.minecraft.class_1309.handler$bjp002$visuality$tick(class_1309.java:6655)
at net.minecraft.class_1309.method_5773(class_1309.java:2499)
at net.minecraft.class_1308.method_5773(class_1308.java:351)
at net.minecraft.class_3218.method_18762(class_3218.java:739)
at net.minecraft.class_1937.method_18472(class_1937.java:480)
at net.minecraft.class_3218.method_31420(class_3218.java:385)
at net.minecraft.class_5574.method_31791(class_5574.java:54)
at net.minecraft.class_3218.method_18765(class_3218.java:353)

-- Entity being ticked --
Details:
Entity Type: minecraft:rabbit (net.minecraft.class_1463)
Entity ID: 1
Entity Name: Rabbit
Entity's Exact location: -10.81, 111.00, 29.09
Entity's Block location: World: (-11,111,29), Section: (at 5,15,13 in -1,6,1; chunk contains blocks -16,-64,16 to -1,319,31), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,-64,0 to -1,319,511)
Entity's Momentum: 0.00, -0.08, 0.00
Entity's Passengers: []
Entity's Vehicle: null
Stacktrace:
at net.minecraft.class_1937.method_18472(class_1937.java:480)
at net.minecraft.class_3218.method_31420(class_3218.java:385)
at net.minecraft.class_5574.method_31791(class_5574.java:54)
at net.minecraft.class_3218.method_18765(class_3218.java:353)
at net.minecraft.server.MinecraftServer.method_3813(MinecraftServer.java:897)
at net.minecraft.server.MinecraftServer.method_3748(MinecraftServer.java:824)
at net.minecraft.class_1132.method_3748(class_1132.java:105)
at net.minecraft.server.MinecraftServer.method_29741(MinecraftServer.java:671)
at net.minecraft.server.MinecraftServer.method_29739(MinecraftServer.java:265)
at java.base/java.lang.Thread.run(Thread.java:833)

-- Affected level --
Details:
All players: 0 total; []
Chunk stats: 2209
Level dimension: minecraft:overworld
Level spawn location: World: (0,118,0), Section: (at 0,6,0 in 0,7,0; chunk contains blocks 0,-64,0 to 15,319,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,-64,0 to 511,319,511)
Level time: 11059 game time, 16661 day time
Level name: 1.20 New
Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Level weather: Rain time: 40691 (now: false), thunder time: 145097 (now: false)
Known server brands: fabric
Removed feature flags:
Level was modded: true
Level storage version: 0x04ABD - Anvil
Stacktrace:
at net.minecraft.server.MinecraftServer.method_3813(MinecraftServer.java:897)
at net.minecraft.server.MinecraftServer.method_3748(MinecraftServer.java:824)
at net.minecraft.class_1132.method_3748(class_1132.java:105)
at net.minecraft.server.MinecraftServer.method_29741(MinecraftServer.java:671)
at net.minecraft.server.MinecraftServer.method_29739(MinecraftServer.java:265)
at java.base/java.lang.Thread.run(Thread.java:833)

You're probably trying to run visuality 1.19.4 on 1.20

I have the same issue, running 0.7.0 for 1.20 (curseforge says that version also works for 1.21) minecraft 1.21. Happens as soon as I load into a world or a server.

You might confuse 0.7.0+1.19.4 and 0.7.0+1.20 versions, this issue only occurs when you're trying to run visuality 1.19.4 on 1.20 or 1.20.1, get this https://www.curseforge.com/minecraft/mc-mods/visuality/files/4571997, it does support 1.20.1 but not 1.21(it doesn't exist)