The later Milhouse LibreElec 9 for Kodi 18.2 (Generic) test builds using Linux 5 have ALSA problems on NUCs (no Passthrough Audio). I’m hoping this will resolved with official LibreElec 9.0.2 build.
I’ve had to stay with last Milhouse LE build using Linux 4.19 to use Passthrough.
Have you tried the blacklist fix suggested by Milhouse?
Code
echo "blacklist snd_soc_skl" >>/etc/modprobe.d/blacklist.conf
reboot