Onboard audio device Intel Cannon Lake PCH and 9th Generation Intel CPU probably has a built-in digital microphone array (DMIC) that is not supported by the usual snd_hda_intel driver
system requires a different driver for the DMIC from package sof-firmware
But SOF drivers did not work well when first released and needed a number of patches to work on laptop systems
The usual modprobe.d option for these systems was a workaround to disable the internal DMIC
so the rest of the sound card would use the ‘legacy’ snd_hda_intel driver
# /etc/modprobe.d/alsa.conf
options snd-intel-dspcfg dsp_driver=1
(Ubuntu may have used an older option snd-hda-intel dmic_detect=0 but that option is no longer supported by kernel v5.8)
But if use of internal DMIC is needed, system needs package sof-firmware installed and a later version of PulseAudio (v13.99) that has patches included for the DMIC
See this discussion for how to switch to Manjaro testing branch to get the development version of PulseAudio - Problems with audio on laptop