Note here is another thread where users with LEAP-15.6 and a computer with Tiger Lake hardware for sound, are having intermittent issues, where sound would not work after a fresh boot, or even after a reboot, but after a number of reboots sound might come back.
I have had something similar with my laptop (which has Tiger Lake sound hardware) but as of my last few boots, sound has worked. Given the problem was intermittent, I don’t know if recent updates addressed the issue. Here is a link to the other thread (no solutions per se - other than if sound fails after rebooting a few times, try to boot to an older kernel):
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