Well according to Configure Graphics Cards - Manjaro :
note: The mhwd profile ‘video-linux’ corresponds to the latest opensource driver available for your hardware.
and you wouldn’t want that interfering in any way.
I would try in a tty ( following the instructions in GitHub - Askannz/optimus-manager: A Linux program to handle GPU switching on Optimus laptops. & https://wiki.manjaro.org/index.php?title=Optimus_Manager ) doing the following again:
- remove optimus-manager
- remove video-linux
- remove video-hybrid-intel-nvidia-450xx-prime
- install video-hybrid-intel-nvidia-450xx-prime
- install optimus-manager (from the repo) and configure it