and of course the Acer bios updater for this old laptop requires Windows because it's a .exe file π
and of course the Acer bios updater for this old laptop requires Windows because it's a .exe file 
rpm-ostree install, where you need to run rpm-ostree kargs manually..exe you found requires some undocumented arguments.set-kargs:
rpm-ostree kargs \
--append=rd.driver.blacklist=nouveau \
--append=modprobe.blacklist=nouveau \
--append=nvidia-drm.modeset=1

rpm-ostree kargs to add boot arguments.rpm-ostree kargs.rpm-ostree kargs command lists the same kernel arguments. So I suspect they are just using this as a method to update the cfg file that is symlinked to /boot/loader/grub.cfgrpm-ostree kargs is most likely just a tool for quickly editing the etc file.
cat /proc/cmdlinenvidiakargskargscmdlineos-isogenerator/installer/kickstart/ublue-os-nvidia.ks
7:bootloader --append="rd.driver.blacklist=nouveau modprobe.blacklist=nouveau nvidia-drm.modeset=1"just set-kargs/etc/default/grub/etc//etc//etc//etc//etc/ostree/usr/etc//etc/kernel/cmdline