I agree, it’s not satisfactory. I use an external monitor which switches it to Nvidia (,while using Intel on laptop) but if you want to use it on your laptop it’s not ideal. That’s why I will never purchase Nvidia or hybrid laptop again if I can avoid it.
To switch to Nvidia in bios and blacklist nouveau I suggest to follow Lenovo’s installation instructions of Linux on hybrid laptop (ignore how they install Nvidia driver, not relevant on Arch). That worked for me but faster battery drain. 
Edit:
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make sure to backup your data, or first fresh install and experiment
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you could try to blacklist nouveau first, and see if the nvidia on Optimus works and there might be sort of a conflict between cards. Note that I generally use the package
optimus-manager -
you can try to blacklist nouveau temporarily after switching to Nvidia in bios, press e on boot in grub and follow
Blank Screen right after new update - #68 by joekamprad -
here the code I found to blacklist nouveau in the grub config to make it more permanent. Perhaps @ricklinux can confirm this is right, haven’t done this for a while
#edit the config file
nano /etc/modprobe.d/blacklist-nouveau.conf
#add following
blacklist nouveau
options nouveau modeset=0
#Update the initramfs image then reboot the system
sudo update-initramfs -u
sudo reboot
My two cents just in case you want to try. Note blacklisting can be reverted, you can always go back to TTY, fix things and boot back to gui. Never panic (I did that in the past), everything is fixable.