Hello,
If you can either chroot in or boot into runlevel 3
(see [HowTo] Resolve an unbootable Manjaro (black screen, login failed, cant boot, etc))
Then lets look at your drivers:
mhwd -l -li
If you have, for example video-nvidia then remove it:
sudo mhwd -r pci video-nvidia
Then maybe try to force reinstall the open drivers (this should be your only gfx profile):
sudo mhwd -f -i pci video-linux
Then reboot (systemctl reboot)