I downloaded the Surface Diagnostics Toolkit from Surface.com/Tool and ran through the program. So far, my keyboard and mouse lag is gone. I'll keep you posted if it comes back.
BTW, here's the link to download the Surface Diagnostics Toolkit. https://aka.ms/surfacerepair
I downloaded the diagnostics toolkit and ran it. I was coming back to this thread to report that it seemed to have improved or fixed the lag issues but...
...(drumroll)...
...it didn't.
As soon as I started typing in this reply box (i'm using Edge, btw) the lag came back with a vengeance. It's gone away again while I'm typing but I definitely just got a 10 second block of lagging.
:-(
-Ben
Yes, I saw the early reference to the toolkit, and didn't get a chance to respond. I tried that as well with no difference.