What motherboard do you have? Also what happens exactly when the lock-ups happen? Have you ever been playing audio when the lock-ups happen and does it loop or stop or keep playing?
I recently had to “fix” (workaround) a similar issue in the OpenBSD kernel with a specific hardware peripheral on my PC (running a 2nd-gen Ryzen), the High Definition Audio controller. For whatever reason (and only when I was running OpenBSD) interrupts from the HDA controller (to let the CPU know to refill audio buffers) would just randomly stop making it to the CPU and audio would loop for a few seconds and then shut off. I spent a long time trying to figure out what causes it and reading Linux driver code but I couldn’t find a cause or why only OpenBSD would trigger it. I ended up having to write kind of a hacky polling mode into the HDA driver. My only guess is some of these AMD-chipset-having motherboards have faulty interrupt controllers.
Maybe there is a similar issue with your system and timer interrupts aren’t making it to your CPU or something. But I’m not really an expert on PC architecture and idek if it even works like that on PCs lol
Sorry for so many questions but do you also have any kernel logs available from when this happens?