As a former arch linux guy, the solution to this is to be prepared by having a separate partition for home, and a bash script to reinstall f---ing everything again with a single command.
First of all, almost any Arch update induced problem can be solved by downgrading the offending package to the previous version, which handily is available in /var/cache/pacman/pkg/. This is an essential Arch troubleshooting skill.
Even an unbootable system (which has only happened once in my 10 years of using Arch because I didn't read important news) can be fixed this way, because you can always boot from the installation usb stick and then use arch-chroot to access your installation and fix problems.
Secondly, if the problem was indeed caused by an Arch update, you will just reinstall the problem if you run a reinstall script.
Well you see, I didn't know that haha, I know there are better ways to deal with a "defective" arch update but to me, that was the easiest, laziest way to do it and it worked most of the time. I have to admit this was a "me" problem I'm not blaming arch it's just that I grew tired of things breaking because I didn't read the news before doing pacman -Syu.