On a clean install with Minecraft 1.19.3 and FabricLoader 0.14.12.
This mod causes a crash with MemoryLeakFix.
I tested it with only these 3 mods:

• fabric-api 0.71.0+1.19.3
• memoryleakfix 1.19.3-0.7.0
• universal-graves 2.2.0+1.19.3

Then starting an existing world or a new world produces a crash/disconnect.
Removing memoryleakfix or universal-graves and starting a new world works.

Log: latest.log

Reported as MemoryLeakFix#67

Install latest polymer version

Thanks, that fixed it