...with my Z390 Designare:
I have installed one 16GB memory module (G.SKILL - F4-3000C16Q-64GTZR)in bank A1. Everything works perfectly!
With two, three or four modules the LAN / WLAN is deactivated. It does not matter in which slot the modules are inserted.
...here my experience with macOS Big Sur 11.4 (20F71)
VT-d enabled in BIOS
Edit: The following two steps are not necessary. The system works flawlessly even with activated XMP profile and the higher clock rate of the memory.
XMP profile disabled in BIOS
I also have the network errors and for me the DMAR table appears under MaciASL. Nothing is entered in the config.plist under "ACPI - Delete".
...as a quick note, on my ASUS Prime X299 Deluxe, the Thunderbolt-to-Gigabit Ethernet adapter works great. AVB included! It is connected to a Gigabyte...
@Denis1805 ...please try this EFI folder, it is a debug version. The computer will not start again but we get an ACPI dump. On the EFI partition a folder "SystemReport" is created and in it the folder "ACPI". Please attach it here.