I am not sure what is causing this, and despite originally trying to launch the game with a few more mods, launching it by itself presents the exact same problem.
i unpacked the log.gz file and have attached it to this.
2020-10-13-3.log
I have reinstalled minecraft and tried several things, but nothing seems to be working.

I think you might've downloaded the sources jar from curseforge. Make sure you're using the normal binary, if you are still having a problem after that then let me know