So this: journalctl --since "2 days ago" -p "emerg".."err"
yields nothing?
whenever I try to do any command with pacman
Example?
You don’t need to actually do it, you can look in your bash_history for the commands you did.
The command history
will list all your recent commands, the most recent at the bottom of the list
Also, since this could be driver related, please post the output of: inxi -Fazy