If I were to decompile the SSDTs on an affected laptop, would you be able to see if/when the system is entering SMM and what it's doing in there that's taking so long? I've noticed this issue on several Windows gaming laptops with nvidia GPUs over the years and I also started installing event tracing, the intel BIOS tools, etc, but it was all just a bit beyond my depth. I've done some DJ'ing and would like to use my gaming laptop, but the whole system freezing so hard that audio glitches every minute is probably part of why the "nobody uses Windows for live audio due to latency spikes" thing is so widespread. Not to mention it makes, you know, gaming unpleasant.
Likely able to identify that it's entering SMM, unfortunately not able to demonstrate what it's doing inside there.
Would it be practical to patch out any SMM calls and get applications to run more smoothly?
It's not super easy under Windows and it would likely disable dGPU power management. Easier to patch the DSDT not to send those notifications (although that's still not super easy under Windows)