I'm at a stage where I don't want to be doing network management on my weekends. I have a Ubiquiti router that's pretty good, and for my router I'd like something like TrueNAS for my NAS, a distribution that completely turns the hardware into an appliance I can configure once and forget about.
Is there something like that?
Pfsense/opnsense would be one option (based on FreeBSD). For Linux there is OpenWRT, which you can either run as an alternative firmware on quite a few consumer routers/access points, or install on a PC or Pi or similar.
Caveat: I have only used OpenWRT on a high end consumer router (GL.inet MT6000) out of those. That works well, anything else is based on reading about people using those options.
For all of those, once you set it up you don't really need to do much except install updates a couple of times per year, or if you want to forward a new port or such.