Edit: 3/1/2024
It seems that a lovely side effect of of this Plymouth update, and having to add a early KMS setting in GRUB for this black screen issue, is that it appears to have finally fixed my long time screen tearing issue with my Nvidia GeForce GTX 970 using the proprietary driver.
From a previous post that I cannot seem to edit to show a fix:
I had dimly recalled after doing this black screen fix that something about early KMS was mentioned for screen tearing. And indeed I was right. User bogdancovaciu mentions it in the first comment after my initial post. Back then I was very new to the Manjaro and Arch based Linux distributions in general, so adding early KMS at the time, was more than I knew how to do.
It is nice that with some time and experience on Manjaro, these fixes become less of an obstacle and challenge.
Thank you for your help linux-aarhus.
It appears that the kernel mode parameter nvidia_drm.modeset=1 was all that was needed for my Nvidia with proprietary driver system.