I've been running OpenBSD on an APU2 as a router for over a year (and on the ALIX it replaced many more years).
OpenBSD makes it so dead simple to setup the basics that (unlike with my NAS) I've never been tempted to try a GUI distribution such as pfSense, yet it also gives you the flexibility to do more esoteric things like forwarding DNS using DNSCrypt, or allowing UPnP, but only to the PlayStation on a VLAN that can't talk to your main network. And the PC Engines gear works perfectly with OpenBSD.
OpenBSD makes it so dead simple to setup the basics that (unlike with my NAS) I've never been tempted to try a GUI distribution such as pfSense, yet it also gives you the flexibility to do more esoteric things like forwarding DNS using DNSCrypt, or allowing UPnP, but only to the PlayStation on a VLAN that can't talk to your main network. And the PC Engines gear works perfectly with OpenBSD.