After contacting support about the BIOS issue, I returned the motherboard.
I got a refund. I got a new unit from Amazon a few weeks ago.

With the delay, I opted for a 92mm fan build.

• 92mm fan area on heatsink: 52.90cm² / 53.13cm² (99.6%)
  • Estimated airflow (99.6%) 57.27 m³/h
  • Static pressure 2,11 mm H₂O
• 120mm fan area on heatsink: 54.63cm² / 89.72cm² (60.9%)
  • Estimated airflow (60.9%) 57.36 m³/h
  • Static pressure 1,53 mm H₂O

The aftermath math seems to indicate similar airflow, relative to cover heatsink area, however the static pressure is better with the 92mm fan.

The 92mm fan makes of an overall nicer build. The 14mm height allows for an 2mm acrylic support with 4 mounting holes.

There is small gap between the support plate and the heatsink. Perhaps air could be sealed a bit more to flow out the back.

When putting on the IO plate, I realized that the antenna connector are SMA rather than RP-SMA. Since the antennas are provided I understand the choice, however it needs to be noted that WiFi generally uses RP-SMA pigtail. I wanted to use small antenna screwed on the back directly thus had to change the pigtail which was very annoying. I would guess people are likely to connect other antenna and get bad performance since there is no pin connecting the pigtail signal to the antenna.

Overall the fit is quite nice.

I added a custom RED LED strip that can be controlled from the FAN PWM.

The thermals are acceptable with between 75°C to 90°C considering the 100W consumption of the CPU.

I noticed that under high boost the thermal get pretty high. However with all core loaded at 4.4GHz, the system hold around 80°C. I need to tweak the PWM curve.

The new motherboard does not have the BIOS issue.
The NVME are enumerated correctly with each 4 lanes at full speed (Gen4, Drive limited).

I had plan for a Ryzen 9 7900 build to be conservative with power and heat.
This build kind a match a Ryzen 9 7950X, in a 3.3L case!

The system is quiet when idle except for the PSU fan.