Excellent article.

I do not have the same technical depth to dig this far as the author, but this kind of problem seems pretty common on laptops, especially those with "switchable" iGPU/dGPU setups.

I had an Acer laptop about 7-8 years ago with almost the exact same latency symptoms. In the end I just disabled the dGPU in the BIOS (since I only used it for office work), and that instantly solved the issue.

This kind of thing is very infuriating because not only is it hard to track down the root cause (which I am very grateful the author did), but it is also even harder to get the vendor to actually acknowledge or fix it.