Ubuntu 18.04 fresh install on Acer: Sound output "Dummy Output", no input

Question

I have installed Ubuntu 18.04 on my Acer aspire VN7.

Problem: As sound output I get only "Dummy output". For sound input I get nothing at all. If I plug in headphones nothing happens. If I connect a soundbar via bluetooth it is displayed as the only output (dummy output disappears) and I can play music.

$ lsmod | grep snd_hda_intel
snd_hda_intel          53248  0
snd_intel_nhlt         20480  1 snd_hda_intel
snd_hda_codec         131072  1 snd_hda_intel
snd_hda_core           90112  2 snd_hda_intel,snd_hda_codec
snd_pcm               102400  3 snd_hda_intel,snd_hda_codec,snd_hda_core
snd                    86016  8 snd_seq,snd_seq_device,snd_hwdep,snd_hda_intel,snd_hda_codec,snd_timer,snd_pcm,snd_rawmidi

$ lspci -nnk | grep -A2 Audio
00:1f.3 Multimedia audio controller [0401]: Intel Corporation 100 Series/C230 Series Chipset Family HD Audio Controller [8086:a170] (rev 31)
    Subsystem: Acer Incorporated [ALI] Sunrise Point-H HD Audio [1025:1039]
    Kernel modules: snd_hda_intel
00:1f.4 SMBus [0c05]: Intel Corporation 100 Series/C230 Series Chipset Family SMBus [8086:a123] (rev 31)

$ sudo dmesg | grep -i audio
[    0.179482] ACPI: Added _OSI(Linux-Lenovo-NV-HDMI-Audio)

My attempts to solve the problem:

• followed this instruction to add options snd-hda-intel model=generic to my /etc/modprobe.d/alsa-base.conf (https://www.linuxuprising.com/2018/06/fix-no-sound-dummy-output-issue-in.html). Does not solve the problem and I realized that this line was already there. Also tried to change the option to auto.
• tried each method described here: https://itsfoss.com/fix-sound-ubuntu-1304-quick-tip/
  • sudo alsa force-reload
  • reinstall alsa-base pulseaudio
  • mv ~/.config/pulse ~/.config/old_pulse and reboot
  • sudo gedit /etc/default/speech-dispatcher RUN option was already no
• tried to use pavucontrol as described here: Sound going to dummy output on 18.04
• pulseaudio --kill && pulseaudio --start (Ubuntu 18.04 sound doesn't work, dummy output)
• sudo modprobe -v snd-hda-intel from the same post gives no output for me
• edit /etc/pulse/default.pa (https://www.linuxquestions.org/questions/linux-hardware-18/ubuntu-18-04-dummy-output-and-sound-disappeared-4175659386/)

I'm going forward to hearing your suggestions ;)

Update:

Setting back all files in /etc/pulse/ as supposed by mchid does not work (https://askubuntu.com/a/800280/167115)

But I found out something interesting/strange. If I boot Ubuntu 18 live from USB, sound works perfectly (output and input). So I compared /etc/modprobe.d/alsa-base.conf, /etc/pulse/default.pa and /etc/default/speech-dispatcher. They are identical.

Next I compared the packages which are installed between these two systems (apt list --installed). I found pulseaudio-module-bluetooth and libcanberra-pulse which are installed in the live version but were not installed on my installed OS. This was not the problem, still dummy output.

Answer 1

There seems to be a problem with 5.3.0-42-generic uname -r. I set my kernel to 5.3.0-28-generic (Set "older" kernel as default grub entry) and now sound works just fine.

PS: Ok, I'm pretty sure that someone suggested to change the linux kernel here, but now this answer has disappeared and I have to answer it myself. Thank you mysterious stranger ;)