Following up with a necro update lol.
Picked up a EVGA RTX 3080 FTW3($650) now that GPU prices are back to reality.
Ran into some differences between the build posted above.
So MKII S1 the GPU is mounted 2.5mm higher then MKIII S1 and my RTX 3080 hyrbid FTW3 has 3 power connectors instead of 2. Those 2 delta means that my MKII S1 wont work for this build. Luckily MKIII are 50% on AMZN so I bought one.
I think the MKII with the original 3080(2 power connectors) would work. But the 3 power connector runs into interference with the hoses out of the radiator. The top grill just barely doesnt close so that 2.5mm also coming into play for the delta between MKII and MKIII S1s.