Do you update the kernel every week?
Linux is an awful choice for routers: too many exploits and ultra fast cycle of updates/features plus there are number one target...
Too many exploits is not a that big problem. Non of new fancy exploits with cvss 10.0 from 2026 have worked for this ap. If you don't use all the drivers you have small attack surface. I'd say that it's a surviviourship bias. Bsd has less traction => less bugs found
That hasn't been my experience as long as you keep an eye on updates. Luckily openwrt has made this really easy to upgrade when required.
Is Linux riddled with remotely exploitable vulnerabilities? A router shouldn't be running a lot of untrusted code.