So, I recently built a new computer. Originally had planned a Z370 with GC-Alpine Ridge 2.0 card.
The Z370 Motherboard I originally bought was DOA so I returned it and purchased a Z390 Ultra instead.
The Alpine Ridge card seemed to work OK even though the Z390 was not on the supported motherboard list.
It shows up in BIOS, and devices plugged into it seem to work great.

However, I am seeing issues with the computer not being able to sleep, and rebooting on shutdown instead of powering off.
When it sleeps or shuts down, the power clicks off, LEDS turn off etc.. then 2 seconds later it powers back on by itself.

These issues disappear when I remove the GC-Alpine Ridge card.

I am not opposed to the idea of having to buy a Titan-Ridge card. I know full well that the Alpine-Ridge is not supported on the Z390, even though I dont really understand WHY.
However, I am wondering if folks think this is an issue that could be solved with a BIOS update (modified bios or otherwise).

Also curious if anyone else has experience with either the Alpine OR Titan ridge add-in cards with a Z390 Ultra (or one of its cousins).
My fear is that I am going to go thru the hassle of sourcing a Titan-Ridge card.. and they are tough to find right now... and spend over a hundred bucks on the thing only to see the same issue.