At first I thought some of the problems I'm facing were related to virtio-net-pci network type. So I've switched to e1000.
Eventually I've found the issues are not related to virtio-net-pci and reverted back to this configuration which works well.
So bottom line, no need for taking E3522X2.EFI driver nor using e1000 (at least in my case).
Note for completeness: -global virtio-net-pci.romfile="" is required for the VM to operate.
It was pleasant discussing with you on this thread, by no means I take it for granted your questions, answers and guidance which helped a-lot. Really appreciated.