The crash you sent happens during rendering, but Snow Under Trees is a server side mod.
Please report crashes in a fork or port to that fork or port first, and let the author decide whether the issue needs to be reported upstream as well or not. The fork or port may be doing something different to the original, and the issue may not even appear in the original. You wouldn't tune your car, then go to your car dealer instead of the mechanic when something goes wrong with the tuned parts.
the bug appeared on "https://github.com/mineblock11/snow-under-trees-fabric", a fork of this project. the original project (this project) is not tested,but i think the issue should be reported here
the mod caused Minecraft to crash when the world finish loading
it seems to be a render thread error crash-2023-05-01_14.57.08-client.txt here is the crash report
2023-05-01-7.log here is the log
your project is really great, but it will be greater without this bug!