Stuck on connecting to the realm when data pack is enabled

This actually affects version 1.21.3 as of posting

When we try to enable my custom enchantment datapack, we have trouble connecting to the realm

Steps to Reproduce:

1. Download datapack
2. Create new world, and add the data pack through the world creation menu
3. Select the world with the datapack as the active world for the realm
4. Attempt to connect to realm

Observed Results:

Game is stuck on the "Connecting to realm" screen, or "an error occurred" message flashes onscreen

Expected Results:

Client connects to realm