Yes, it is feasible to operate Windows on a router.
Yes, it is feasible to operate Windows on a router.
If your router is an x86 PFSense box, that's it. Otherwise, it's not possible without the necessary abilities.
Many routers aren't built for ARM, let alone x86. They typically use MIPS processors. Even if Windows were moved to MIPS, it wouldn't work well due to the limited resources routers have. While you could run an old x86 system with PFSense, having it and Windows running simultaneously in the same machine would be risky. I doubt that's your main concern.
I've noticed more ARM-based routers, but that could just reflect confirmation bias. For example, the Linksys model I own is a 1.6GHz dual-core ARM with 512MB RAM and even a SATA II port. Although the CPU might handle Windows 10 ARM at a slow pace, the limited RAM would be problematic and the absence of a GPU would be a major drawback—routers usually don't come with those features built in!
If you're wondering if Windows can work as a router, the response is yes. You'll need a computer running Windows and at least two Ethernet ports. One guide covers this with Windows Server 2019: https://msftwebcast.com/2020/02/configur...outer.html. If you're thinking about installing Windows on a router, it's uncertain—most consumer routers aren't built for i386 or amd64 architectures. Some enterprise devices do support Windows, like certain models from Lanner.