mate-optimus or nvidia-prime packages generate a module blacklist file to prevent nvidia graphics from starting:
This file was generated by nvidia-prime
blacklist nvidia
blacklist nvidia-drm
blacklist nvidia-modeset
alias nvidia off
alias nvidia-drm off
alias nvidia-modeset off
Try to use udev to disable dynamic discovery and use of nvidia
Use lspci | grep -i nvidia
cat >/etc/udev/rules.d/10-remove-nvidia-audio.rules
ACTION=="add", KERNEL=="0000:01:00.1", SUBSYSTEM=="pci", RUN+="/bin/sh -c 'echo 1 > /sys/bus/pci/devices/0000:01:00.1/remove'"
cat >/etc/udev/rules.d/10-remove-nvidia-video.rules
ACTION=="add", KERNEL=="0000:01:00.1", SUBSYSTEM=="pci", RUN+="/bin/sh -c 'echo 1 > /sys/bus/pci/devices/0000:01:00.0/remove'"
update-initramfs -u
Also learned a little from a nice French ALSA page explaining that the so called intel_hda sound card has nothing to do with having an actual Intel microprocessor: it is actually an intel standard that has been copied, implemented and extended by many manufacturers so they are all actually different! Something can go wrong with your ALSA driver of a built-in audio chip with any kernel update so forcing ALSA and Pulse Audio back onto using Nvidia even though it is alsa soundcard number 2, not default. Some intel_hda standard chips can be woken and restarted with cheat code options in the alsa configuration file. For example:
vi /etc/modprobe.d/alsa-base.conf
options snd-hda-intel model=hp power_save=0 power_save_controller=N