I used a water bucket next to snad so I could grow sugarcane, and it crashed my game. I restarted the game, and the chunk that the water was in had a rendering issue. I found and picked up the water which fixed the rendering error, but also crashed my game at the same time.
I have added one additional mod as well as updating Tinkers/its dependency, the only mod I added to the pack was Magnesium (as I got a warning when installing optifine)
latest.log

Alright, just confirmed that it's an error with magnesium. I'll keep this here just in case anyone else has this issue.