Can I reinstall after pacman -Syu

My son was having some problems with steam, he is fairly new still to Linux and especially omarchy, I convinced him to give it a try.

Anyway he was following some stuff on-line and did not realize that you cannot do standard updates like this on omarchy. Long story short he can login now but it is a broken system essentially.

I know that normally I have the omarchy-reinstall but I don't see that now on his machine.

Obviously, I can just do a backup of the important stuff and start from scratch, but I was hoping for something a little less demanding on my time as he uses this for school tomorrow.

What is the best way to get him going again, unfortunately I did not configure timeshft on the laptop like on my machine.