Kernel upgrade messes with sound in Chrome

[sl70]

I upgraded the kernel from 6.6.74 to 6.12.16 a couple of weeks ago, and now Chrome doesn't produce almost any sound. Stuff that doesn't work is Netflix, Prime Video, web browser videos. What does seem to work is Zoom -- or at least the audio config page produces sound. I tried the same sites with firefox-bin and sounds come out OK (but Netflix and Prime Video fail with some abstruse error codes). Everything works OK in kernel 6.6.74.
I copied the .config file over to 6.12.16, did make oldconfig, made the kernel and installed the modules, installed the kernel, and generated the grub config file.
I run WindowMaker, no systemd, only enough pulse audio for my bluetooth ear buds to work (actually, they don't work anyway). I run a mixer control app, wmsmixer; for some strange reason, the mixer app runs with /dev/mixer1 for the 6.6.74 kernel, but with /dev/mixer2 with the 6.12.16 kernel.
So, do I have to stick to kernel 6.6.74, or is there some way to get sound with a more modern kernel?