Extremely long boot time and can't get to graphical session after update

Not without some more investigation.

Easiest would be to get a hold of an ISO with an LTS kernel, write it to a thumb drive, boot from it, and enter as chroot environment. From there, logs can be inspected, or retrieved, copied, and provided here.

How to chroot

  1. Ensure you’ve got a relatively new ISO or at least one with a still supported LTS kernel.

  2. Write/copy/dd the ISO to a USB thumb drive.

  3. When done, boot with the above mentioned USB thumb drive into the live environment.

  4. Once booted, open a terminal and enter the following command to enter the chroot encironment:

manjaro-chroot -a
  1. If you have more than one Linux installation, select the correct one to use from the list provided.

When done, you should now be in the chroot environment.

But, be careful, as you’re now in an actual root environment on your computer, so any changes you make will persist after a restart.

From the chroot environment run the following:

journalctl --boot --priority=3 --no-pager

This will output all Warnings and Errors encountered during the boot process.