hAP ax3 ether1 for wan?

Been following http://forum.mikrotik.com/t/using-routeros-to-vlan-your-network/126489/1 and building a config based on the guest example adapting it to also include a work isolated network.

This config: https://forum.mikrotik.com/download/file.php?id=46392

I notice it is using ether1 for wan.

# Yellow WAN facing port with IP Address provided by ISP
/ip address add interface=ether1 address=a.a.a.a/aa network=a.a.a.0

/interface list member
add interface=ether1     list=WAN

Isn’t ether1 the 2.5gbit PoE port on the hAP ax3?
Would it be better to use ether5 as the wan interface leaving ether1 available for LAN?

is it a simple as changing the config to reference ether5 instead of ether1 or would additional config be required?

Default config on most ROS devices is indeed to have eth1 as WAN but you can change it as you wish.