Pack is running VanillaFix so I don't crash out until i try to disconnect from the server. Here's the crash log:
https://paste.dimdev.org/apowagarog.mccrash

Doesn't look particularly related to Streams, what makes you think it is?
When does this happen? Any time you join a world? Only when specific things are in view? Seemingly at random? On disconnect?

Client Crashes Since Restart: 6

While VanillaFix's crash-recovery may be convenient, it's by no means infallible and may leave the game in an invalid state (causing further errors that would have never happened on their own). As such, I'll only consider the very first crash report when VanillaFix is installed.

Please post the full game log. There's a good chance it'll contain the first crash report as well.
Also try to remove as many unrelated third-party mods as possible.