The manual seems to indicate that the graphics card has to go in the first slot for a single board. The top two slots for a dual graphic configuration and so on.
Not sure that helps any.
I am running the 11,900K and it seems pretty fast once in Windows.
I am however having some slow times to post but I believe that may be due to having a large number of drives internal and external.
Good luck getting that 3080. Prices are ridiculous to the extreme. I've been waiting for the MSRP prices to return to normal. Not hopeful. Till then I am using the onboard Intel 750 through the two USB-C/TunderBolt connectors on the back of the motherboard as well at the HDMI connector (Dual Monitor and a Drawing Tablet with screen)
Hope that helps.