If all you need is a router, Mikrotik also offer stellar support, lots of configuration options and are much cheaper for the same specs.
Try watching MandaloreGaming videos on the series. They are long, but explain a lot.
Well, the Aleph One project was there a long time.
Didn’t see it mentioned — SingleFile is an awesome tool to save the whole page as a single compatible with everything HTML file with embedded css and images.
UPS depends on usecase and on the stability of your electrical supply (which varies greatly from place to place). I just leave everything running and have it configured to restart automatically on power restore (if it fails, which it rarely does).
A rather different take on casual arcade racing, but I quite like Wreckfest.
This one is more or less comparable I believe. No idea about FOSS though, if it’s important then my advice is invalid, of course. But if I personally was going for a FOSS router, I’d just get an old-ish computer with several NICs inside and install some BSD on it.