HI!
I had exactly the same problem. I installed Endevour OS to an old laptop which originally used Optimus drivers to switch automatically.
I tried the NVIDIA installer with bumblebee, but it did not worked very well. I solved the problem by installing optimus-manager. it is at the end link
This allows you to choose which card to use, and by default uses the Intel so you to avoid the black screen. Although, I wanted to use the NVIDIA drivers, but there seems to be a conflict between the nouveau and NVIDIA drivers, so I blacklisted the nouveau creating a file
/etc/modprobe.d/blacklist.conf
with
blacklist nouveau
blacklist lbm-nouveau
options nouveau modeset=0
alias nouveau off
alias lbm-nouveau off
I was able switch between NVIDIA and Intel cards. I also regenerate the initramfs, but
I don’t know if this step was necessary. I hope this helps.