When going around a world I am getting a few world gen errors, most noticeably what happens is the chunks just stop loading to where the world looks like it ends on an edge:
And then it crashes the game after a while, but when I load the world back I get tons of chunk gen errors like this:
Also sometimes for random reasons it just gives me an immense amount of FPS lag, I'm not sure if it has anything to do with this but just stating that it happens.
Here's the log file: https://pastebin.com/C5hHaZEv
Also another note I removed optifine from the mods because I thought that was what was causing it but turns out that's not it. Because the pictures above were after I removed it. I have since added it back.