Question Lenovo Yoga 6 13ARE05

[amsdj]

I have a Lenovo Yoga 6 13ARE05 laptop with a keyboard issue where most all the letter keys work but just about every other key without a letter doesn't work. This issue persists outside of windows as I've tried in Parted Magic and winPE. I have tried reinstalling drivers from the Lenovo website, reseating the keyboard flex cable, and even installing a replacement keyboard. At this point, I assume it has to be a motherboard fault. I would like to know if anyone else has experienced this problem and if there is a remedy.