The above xkcd comic illustrates a particular mindset that is responsible for the wealth of Linux distributions targeted at users new to the platform. Given this, I don’t have a one-size-fits-all recommendation; each user has different needs, so pigeonholing is counterproductive. For instance, someone that feels more comfortable with an interface akin to macOS could have a bad time with Linux Mint, even though Linux Mint is a great OS for many people.
However, I’ll share a quiz I find helpful, as well as what works for me.
Check out LibreHunt. LibreHunt does a good job of explaining the merits of FLOSS and suggests Linux distributions based on how the questionnaire is answered.
I like OpenBSD. See “Why OpenBSD?” for more details.
It’s best to use a privacy respecting OS here, too. GrapheneOS is what I use, although LineageOS supports a wider range of hardware.
A router is a computer too. Proprietary consumer firmware isn’t exceedingly capable, nor is it secure. DD-WRT, OpenWRT, pfSense, and OpenBSD are all much better options. If flashing firmware onto a consumer router, use Ethernet and take the appropriate precautions.
Check out Building an OpenBSD router for more information on how I approach it.