Edit: Aaahhh Eric is here to the rescue, so don't pay too much attention to what I say :)
From chroot edit /etc/66/init.conf and switch verbosity=4 so you get maximum feedback on console.
If print on console is too small on grub.cfg you can alter the gfx line to a lower resolution so print is larger.
set gfxmode=1024x796x24
or 800x600 etc.
If you are using grub hit e on the menu item for that kernel take out quiet and splash from the entry before you boot.
If the console switches resolution before things freeze at least you have reached udev, mount-udev is a dependency for mount-pts but if something is wrong with mount-udev mount-pts will also fail. If mount-pts fails your system is ro so there is nothing hard to write a copy of the current log to so you can read later. I am suspecting an error in firmware missing that throws udev off.
The /run directory in obarun is a mount point for a temporary file system that is created during boot. Nothing in it is accessible after booting from another system. If you are using arch-chroot from obarun live into the installation what you will see in run is the live system's /run mounted into the chroot. If you mount the installation to say /mnt before you chroot try ls /mnt/run it will be empty.
If your /etc/fstab is ok and mount -a in chroot doesn't result in errors then something must be missing from the kernel and it can't mount file systems. Have you tried reverting back to an arch or obarun kernel that worked before?
example:
# pacman -U /var/cache/pacman/pkg/linux-5.3.13.1-1-x86_64.pkg.tar.xz