Before Elementary I installed Manjaro. Same problem there but we fixed it by inserting an options statement in the file named alsa-base.conf which was found in /etc/modprobe.d.... So the statement read options snd-hda-intel model=acl295-hp-x360, saved the file using sudo nano and then reboot and there was sound.
No live linux distros I have tried (many) have sound, seems they all have a hard time identifing and setting up this HP Laptop sound hardware ACL295.
Does Elementary have ALSA conf file that can be modified? I ask because when I use sudo nano, it says /etc/modprobe.d/alsa-base.conf does not exist, so did not know how to proceed? Thank you for any advice you can give.