My son had some problems with servers like CubeCraft just before the app started having this problem.
I wonder if this issue is related to MCPE-121930?
You're not alone. This same crash log happens on my son's iPad Mini (AppVariant 1:iPad5,2:13.)
2.16.210.05(2.16.210) was crashing at the end of the loading screen.
If you delete XBLStorage.json and turn off WiFi/Cellular data, it crashes earlier in the loading screen, but with the same thread throwing the same exception.
Oldest crash log is March 20th.... he's turning feral over not being able to play Minecraft! 😞
Regarding @Robert R's problem with iPads not seeing each other... that was the same problem I had too.
Robert suggested goto main iPad Settings, scroll down to the Minecraft app, and set "Local Network" to ON. That did it! Thank you Robert!
This happened with a "Spellcraft" template single player world on an older iPad mini.
The fire spell was being used excessively to destroy some dummies❓ .
The game lagged a lot and then generated this error.
v1.19.30.