I was able to build a version of the edk2 firmware that allowed me to boot into the install environment. Notes say to disable PCI-e 3.0 - to do so, comment line 33 of this file before building it: https://github.com/edk2-porting/edk2-rk3588/blob/master/edk2-rockchip/Platform/OrangePi/OrangePi5/AcpiTables/AcpiTables.inf
Edit - more lines were added, currently it is line 36. If the file changes again, this is the line you want to comment out:
$(RK_COMMON_ACPI_DIR)/Pcie2x1l0.asl
Sadly, the onboard NIC isn't supported, and the USB NIC Fling isn't supported for ARM. I kept booting to the "No supported adapters, press enter to reboot" screen. I know that the Raspberry Pi supports the Realtek 8153 with the 0bda vendor ID so I tried connecting one but no luck; alt+F1 at the boot screen and "lsusb" confirmed it, no joy. For science, I tried injecting the USB NIC Fling anyway, the driver showed up in localcli software vib list, but alas, not to be.
I tried using an NVMe to PCi-e x4 adapter to connect a supported Intel NIC but it required a separate power supply. I don't think the Orange Pi liked that amount of electricity as it won't boot anymore. I'd say give it a pass until the USB NIC Fling gets ported over. In the mean time, Armbian works well and for the brief time that I had it, ran extremely well as a tiny web server.