The board has two integrated ethernet adapters, here’s the lshw data:

sudo lshw -c network
  \*-network
       description: Ethernet interface
       product: I211 Gigabit Network Connection
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:05:00.0
       logical name: enp5s0
       version: 03
       serial: 24:4b:fe:<redacted>
       size: 1Gbit/s
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi msix pciexpress bus\_master cap\_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=igb driverversion=5.12.8-zen1-1-zen duplex=full firmware=0. 6-1 ip=<redacted> latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
       resources: irq:61 memory:fc900000-fc91ffff ioport:e000(size=32) memory:fc920000-fc923fff
  \*-network
       description: Ethernet interface
       product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0.1
       bus info: pci@0000:06:00.1
       logical name: enp6s0f1
       version: 1a
       serial: 24:4b:fe:<redacted>
       size: 1Gbit/s
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus\_master cap\_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=5.12.8-zen1-1-zen duplex=full firmware=rtl8168fp-3\_0.0.1 11/16/19 ip=<redacted> latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
       resources: irq:24 ioport:d800(size=256) memory:fc814000-fc814fff memory:fc808000-fc80bfff

It seems that the UEFI entry to activate Wake on Lan for PCIe devices only affects the Intel port, i’ve persistently activated WOL for the realtek port by adding a .link file to /etc/systemd/network/foobar.link

[Match]
MACAddress=<redacted>

[Link]
WakeOnLan=magic
# below lines are cloned from original entry in
# /usr/lib/systemd/network/99-default.link
# which is the default link file for all adapters whose section is hereby overwritten
NamePolicy=keep kernel database onboard slot path
AlternativeNamesPolicy=database onboard slot path
MACAddressPolicy=persistent

The arch wiki shows a couple of alternative ways, but this seems to be the most straight forward for me.