Also chiming in on this: I've been running OpenBSD on dozens of PC-Engines boxes for over a decade (first Alix and then APU2), usually as a full-on firewall HA

Also chiming in on this: I've been running OpenBSD on dozens of PC-Engines boxes for over a decade (first Alix and then APU2), usually as a full-on firewall HA pair with CARP/pfsync. The APU2 is VERY capable, hardware-wise, and a bargain at the price they sell it. I've had flash memory die, but never had hardware fail otherwise. I've also done wireless deployments with APU2 and a wifi card, and the range was not great. Things also might be better with better antennas, or under Linux where drivers are likely more mature. I've never run anything but OpenBSD on them.