when i got this crash, the game refused to provide a crashlog, but i have my latest.log and the steps i took to produce this.

1. make a new world with no quests or quest lines
2. make two quest lines
3. give yourself an advancement (using /advancement) that doesn't normally appear until completing the advancements before it so it can show in the advancement selector for advancement tasks (for this one i specifically used minecraft:story/enter_the_nether or "we need to go deeper")
4. make a quest involving getting this advancement in the first quest line
5. revoke the advancement (again, using /advancement) and all the advancements that can make it show in the advancements menu
6. add the same advancement to the second quest line
   that should crash it

here's the latest.log: https://drive.google.com/file/d/1fI0KyUDH2ISR0ErHLiLvP5ycA3SutCWA/view?usp=sharing (because neither pastebin nor hastebin would take the latest.log, i had to put it on my google drive, sorry about that)

i can also record video of me reproducing this crash if needed

i have the better advancements mod installed, just saying this in case that's the reason why this crash happened

Looks like it's a crash by Lucky Blocks, not by this mod

As busted as all those config errors and backup failures are, I don't think that is what killed it. There's no critical error at the end of the log saying why the game stopped. Is this an actual crash or an unresponsive lockup? The latter would explain the lack of an error but also makes this harder to debug.

it was a mix of both. the game did say "shutting down internal server" immediately afterwards, letting me know that it definitely did crash the game, but then due to my computer not exactly being the best piece of machinery, it locked up, forcing me to bring up task manager and forcefully close minecraft. this is also the reason why it doesn't have a crashlog. unresponsive lockups when crashing are common for my computer, however, and the only way for me to prevent them is through optifine (for some reason), which i can't even install, so you would have to manage to reproduce it yourself to get a crashlog. i could also try with a smaller test pack (which i could include optifine in so i could get the crashlog) if needed.