While security for home users is in general good compared to consumer products much of your concern will most likely boil down to knowledge, maintence, functionality and to some extent hardware.
OpenWrt achilles heel is in my opinion maintence, due to the nature of target devices you normally can't update induvidual packages, updates can be disruptive (POLA - https://docs.freebsd.org/en_US.ISO8859-1/books/handbook/freebsd-glossary.html#pola-glossary ) and requires in many cases manual intervention more so than other distributions. This may contribute to do the "set it and forget it" approach simply because it takes time. What you might also want to consider is that functionality can be severely limited due to targeting "low-end" devices / one size fits all approach depending on application.
If you look at dedicated distributions such as opn/pfsense etc maintaince usually requires very little effort and because they usually target faster and more powerful devices you usually see a substantinal difference in terms of functionality, logging and reporting.
Using a generic distro such as FreeBSD, Debian etc is by far the most flexible solution but usually require somewhat more knowledge to configure and maintain, there's also less "integration" of tools ootb (no webui, reporting etc). They can be just as secure as anything else depending on configuration. It also boils down to what you're comfortable with, I personally don't mind using a "full" distro compared to appliance like but I'd also say that they don't exactly replace each other either as it all depends on use case.
One more thing to consider is that more services also (in theory) may serve as more potential attack vectors. While many services wont face "the Internet" at all and your network is most likely not interesting to hack anyway I wouldn't put too much weight on that aspect for a home user.
As for hardware you might want to pay attention to vulnerabilities such as meltdown etc, in all honestly I highly doubt it'll be of a concern for 99.9% of all home users but you should however try to avoid using "broken" hardware if possible.
I personally run FreeBSD as "router/firewall OS" and OpenWrt for wireless APs simply because that's what I'm comfortable with and it's relatively low maintence and offers great flexibility. I do run a bunch of standalone OpenWrt routers/gateways but they're becoming time consuming and will most likely be replaced with a SBC such as the RockPro64 paired with a dual port Intel NIC.