Big thanks to
@RolloZ170 for providing the modded BIOS and helpful Windows tweaking tips! My Q2SR build is almost complete thanks to your help.
Regarding the MS03-CEO motherboard, it's very good, but has a few downsides:
No built-in WiFi. (You'll need an add-in card).
No USB Type-C ports.
Onboard
M.2 slot limited to PCIe Gen 3 (not Gen 4).
And this motherboard's BIOS lacks an S3 (Suspend-to-RAM) sleep option entirely. (And Linux dmesg shows: "[ 2.537665] ACPI: PM: (supports S0 S4 S5)", no S3)
As a result, the system defaults to S0ix Modern Standby.
While this puts the CPU cores into C6 state (good), the fans keep running during standby (disruptive for standby)
Although this motherboard supports S4 Hibernate, I haven't been able to get it working successfully. Attempts result in errors during the suspend process, with dmesg showing (my cpu's Hyper-threading is disable):
"...
[30227.798757] smpboot: CPU 4 is now offline
[30227.801672] smpboot: CPU 3 is now offline
[30227.804806] smpboot: CPU 2 is now offline
[30227.806439] CPU 1 has 149 vectors, 51 available. Cannot disable CPU
[30227.807603] Error taking CPU1 down: -28
[30227.807606] Non-boot CPUs are not disabled
..."
Overall, I think this is a very good motherboard.
Hope this helps!