Hmm - difficult to say - something is weird with the info you posted - but I managed to extract some information
- a fairly only intel CPU providing integrated GPU using i915
- Nvidia gtx 980
I am guessing the Nvidia is somehow causing this.
If you edit the grub cmdline (you did it to remove quiet) and remove quiet and splash - and append the number 3, then use F10 to boot - you should be able to reach a minimal system.
From there you can login using your credentials.
The first thing to do is to rerun the sync process
sudo pacman -Syu
Please refer the recovery guide on foreign packages (AUR) [root tip] [recovery] Basic Manjaro Linux Recovery to remove any custom packages (AUR and the like).
Restart the system and check if this solved your issue.
What comes next is just thoughts - I have no idea if any of this is relevant.
Look into the /etc/X11/xorg.conf.d and check if there is a configuration for nvidia - likely a symlink to a file in /etc/X11/mhwd.d/ and if I recall correct it is named 99-nvidia.conf.
As the intel i915 is usually working - you could move the nvidia configuration file to a backup e.g.
mv /etc/X11/xorg.conf.d/99-nvidia.conf /etc/X11/xorg.conf.d/99-nvidia.conf.bak
Then restart the system - be sure to move your output monitor to the intel gpu output - see if the removal of the Nvidia GPU can make your system boot.
There is several places where graphics and related stuff are configured.
In /etc/mkinitcpio.conf gpu modules may have been injected in the MODULES array and kms is likely referenced in the HOOKS array.
What to change and what to ignore I cannot say - I don’t know your system, I have no idea what is causing it.