ubuntu 21 randomly loses sound

Is this output from a period when sound worked, or from a moment when it didn't?

I am not sure why my answer didn't post.
The sound didn't work during the test.

If you run the alsa info script again when sound is working, then it is possible to compare the files. Maybe that helps identifying the cause of the problem.

I ran diff, and here is the output. It is apparent that I changed kernel, but I doubt it played a role.
I don't see what might be the culprit. Right now, I am able to get the sound through the alsamixer. However, after every rebootthe volume is on zero.

< !!Script ran on: Wed May 5 22:32:30 UTC 2021
---
> !!Script ran on: Fri May 7 01:51:51 UTC 2021
67c67
< Kernel release: 5.11.0-16-generic
---
> Kernel release: 5.12.1-051201-generic
77c77
< Driver version: k5.11.0-16-generic
---
> Driver version: k5.12.1-051201-generic
113c113
< HD-Audio Generic at 0xfc5c8000 irq 95
---
> HD-Audio Generic at 0xfc5c8000 irq 94
115c115
< HD-Audio Generic at 0xfc5c0000 irq 96
---
> HD-Audio Generic at 0xfc5c0000 irq 95
145a146
> snd_hda_intel: dmic_detect=0
155c156
< dmic_detect : Y
---
> dmic_detect : N
176c177
< dmic_detect : Y
---
> dmic_detect : N
494,495c495,496
< Amp-Out vals: [0x47 0x47]
< Converter: stream=5, channel=0
---
> Amp-Out vals: [0x57 0x57]
> Converter: stream=0, channel=0
506,507c507,508
< Amp-Out vals: [0x00 0x00]
< Converter: stream=5, channel=0
---
> Amp-Out vals: [0x4f 0x4f]
> Converter: stream=0, channel=0
557c558
< Amp-In vals: [0x27 0x27]
---
> Amp-In vals: [0xbf 0xbf]
593c594
< Amp-In vals: [0x00 0x00]
---
> Amp-In vals: [0x03 0x03]
796,804c797,805
< crw-rw---- 1 root audio 116, 4 May 5 18:29 /dev/snd/controlC0
< crw-rw---- 1 root audio 116, 8 May 5 18:29 /dev/snd/controlC1
< crw-rw---- 1 root audio 116, 3 May 5 18:29 /dev/snd/hwC0D0
< crw-rw---- 1 root audio 116, 7 May 5 18:29 /dev/snd/hwC1D0
< crw-rw---- 1 root audio 116, 2 May 5 18:30 /dev/snd/pcmC0D3p
< crw-rw---- 1 root audio 116, 6 May 5 18:30 /dev/snd/pcmC1D0c
< crw-rw---- 1 root audio 116, 5 May 5 18:30 /dev/snd/pcmC1D0p
< crw-rw---- 1 root audio 116, 1 May 5 18:29 /dev/snd/seq
< crw-rw---- 1 root audio 116, 33 May 5 18:29 /dev/snd/timer
---
> crw-rw---- 1 root audio 116, 4 May 6 21:37 /dev/snd/controlC0
> crw-rw---- 1 root audio 116, 8 May 6 21:37 /dev/snd/controlC1
> crw-rw---- 1 root audio 116, 3 May 6 21:37 /dev/snd/hwC0D0
> crw-rw---- 1 root audio 116, 7 May 6 21:37 /dev/snd/hwC1D0
> crw-rw---- 1 root audio 116, 2 May 6 21:37 /dev/snd/pcmC0D3p
> crw-rw---- 1 root audio 116, 6 May 6 21:37 /dev/snd/pcmC1D0c
> crw-rw---- 1 root audio 116, 5 May 6 21:39 /dev/snd/pcmC1D0p
> crw-rw---- 1 root audio 116, 1 May 6 21:37 /dev/snd/seq
> crw-rw---- 1 root audio 116, 33 May 6 21:37 /dev/snd/timer
808,811c809,812
< drwxr-xr-x 2 root root 80 May 5 18:29 .
< drwxr-xr-x 3 root root 240 May 5 18:29 ..
< lrwxrwxrwx 1 root root 12 May 5 18:29 pci-0000:04:00.1 -> ../controlC0
< lrwxrwxrwx 1 root root 12 May 5 18:29 pci-0000:04:00.6 -> ../controlC1
---
> drwxr-xr-x 2 root root 80 May 6 21:37 .
> drwxr-xr-x 3 root root 240 May 6 21:37 ..
> lrwxrwxrwx 1 root root 12 May 6 21:37 pci-0000:04:00.1 -> ../controlC0
> lrwxrwxrwx 1 root root 12 May 6 21:37 pci-0000:04:00.6 -> ../controlC1
824c825
< Subdevices: 0/1
---
> Subdevices: 1/1
839c840
< Card hw:0 'Generic'/'HD-Audio Generic at 0xfc5c8000 irq 95'
---
> Card hw:0 'Generic'/'HD-Audio Generic at 0xfc5c8000 irq 94'
851c852
< Card hw:1 'Generic_1'/'HD-Audio Generic at 0xfc5c0000 irq 96'
---
> Card hw:1 'Generic_1'/'HD-Audio Generic at 0xfc5c0000 irq 95'
860c861
< Mono: Playback 71 [82%] [-12.00dB] [on]
---
> Mono: Playback 87 [100%] [0.00dB] [on]
873,874c874,875
< Front Left: Playback 0 [0%] [-65.25dB] [on]
< Front Right: Playback 0 [0%] [-65.25dB] [on]
---
> Front Left: Playback 79 [91%] [-6.00dB] [on]
> Front Right: Playback 79 [91%] [-6.00dB] [on]
886,887c887,888
< Front Left: Capture 39 [62%] [12.00dB] [on]
< Front Right: Capture 39 [62%] [12.00dB] [on]
---
> Front Left: Capture 63 [100%] [30.00dB] [off]
> Front Right: Capture 63 [100%] [30.00dB] [off]
904,905c905,906
< Front Left: 0 [0%] [0.00dB]
< Front Right: 0 [0%] [0.00dB]
---
> Front Left: 3 [100%] [30.00dB]
> Front Right: 3 [100%] [30.00dB]
1025,1026c1026,1027
< value.0 0
< value.1 0
---
> value.0 79
> value.1 79
1034,1035c1035,1036
< dbvalue.0 -6525
< dbvalue.1 -6525
---
> dbvalue.0 -600
> dbvalue.1 -600
1064,1065c1065,1066
< value.0 39
< value.1 39
---
> value.0 63
> value.1 63
1073,1074c1074,1075
< dbvalue.0 1200
< dbvalue.1 1200
---
> dbvalue.0 3000
> dbvalue.1 3000
1080,1081c1081,1082
< value.0 true
< value.1 true
---
> value.0 false
> value.1 false
1107,1108c1108,1109
< value.0 0
< value.1 0
---
> value.0 3
> value.1 3
1116,1117c1117,1118
< dbvalue.0 0
< dbvalue.1 0
---
> dbvalue.0 3000
> dbvalue.1 3000
1123c1124
< value 71
---
> value 87
1131c1132
< dbvalue.0 -1200
---
> dbvalue.0 0
1187,1188c1188,1189
< value.0 3
< value.1 4
---
> value.0 0
> value.1 0
1232d1232
< ac97_bus
1272d1271
< glue_helper
1278a1278
> i2c_hid_acpi
1321d1320
< snd_compress
1329a1329
> snd_intel_sdw_acpi
1332d1331
< snd_pcm_dmaengine
1339d1337
< snd_soc_core
1342,1345d1339
< soundwire_bus
< soundwire_cadence
< soundwire_generic_allocation
< soundwire_intel
1419,1421c1413,1415
< ii alsa-topology-conf 1.2.4-1 all ALSA topology configuration files
< ii alsa-ucm-conf 1.2.4-2ubuntu1 all ALSA Use Case Manager configuration files
< ii alsa-utils 1.2.4-1ubuntu3 amd64 Utilities for configuring and using ALSA
---
> ii alsa-topology-conf 1.2.4-1 all ALSA topology configuration files
> ii alsa-ucm-conf 1.2.4-2ubuntu1 all ALSA Use Case Manager configuration files
> ii alsa-utils 1.2.4-1ubuntu3 amd64 Utilities for configuring and using ALSA

I am sorry, but I cannot identify the root cause.
What I see are differences in
snd_hda_intel: dmic_detect=0
and the loaded kernel modules (e.g. snd_soc_core and soundwire_*)
but in my opinion these values can hardly change while the system is already running and cannot lead to sound disappearing during use.

Sorry, no idea.