For less money than some gaudy gaming wireless router that you end up replacing every 3 years, you can grab a Mini PC with two NICs, a wireless access point, and install OpnSense.
Your life will be irrevocably changed for the better.
Why does it matter ”what its designed for” a router is no better at it then a computer with 10x the brains you can route 10gig through them if you have the nics for it large company use pfsense and the like
Ermmm router have fans mini pc actually doesn’t( at least mine mines fanless) routers also fail to boot but also that not a giant issue either way cause who’s turning on and off their router and any significant interval I have run time of 6 months before mines restarted and that’s due to software updates otherwise it would push a whole year
I have never had a household router that had a fan in it.
Fanless mini pcs do exists they are rarer and usually more expensive and weaker.
The rebooting problem comes from micro interruption in the power grid. Yes you can add a UPS, but then these will become the main reason why the internet is down (I have a whole stack of APC branded UPS with failed batteries)
Newer WiFi 6 routers tend to have fans cause they get fairly warm but I’ve had a ups on mine for literally years and had to replace the battery in it once but before I got one even I still never had that problem we haven’t had a power outage in like a year or 2 now and I maybe happens once a year if it does so I don’t see your problem and I have it set to auto turn back on when it gets ac power so it’s a non issue