I've been buying these little boxes from AliExpress for years to use as firewalls and routers. My oldest one is almost 9 years old now! OpenBSD installs just fine. Just a BIOS tweak to always boot up after power is restored.
@madcaesar@otl It's a small server running OpenBSD, configured to operate as a router and/or firewall.
Linux and the *BSDs can operate as very good routers and firewalls, usually being much more configurable and enabling you to do more complex than off-the-shelf consumer-level hardware routers. Using them on a small form factor computer with a cheap switch in front of them can give you a better performing and nicer to use alternative.