In terms of driver support these intel systems are the easiest to work with in Linux. Very mainstream and well established drivers.
Requirements may vary.
And I've got no regrets about using a Pi 4 a router. It's sitting on the shelf next to me, and has been trouble-free for over four years now.
You may not care but I do.
I suppose a Pi 4 is fast enough to route 1 Gbps even through a usb network card?
[I do have one "sitting on a shelf" as a home Minecraft server btw. I hate the usb ssd hanging off it.]
I upgraded my home LAN to 10gb/2.5gb early last year, and the RPi can't really keep up with it anymore. I'm using an N305 based mini-pc with 4 ethernet ports for my router now... exceeds my needs and runs great. My home server is an AMD 5900HX based mini-pc with also works very well (ProxMox, Docker, etc).
I mean: There's not much to it. LAN port, WAN port, MicroSD storage, and a (completely optional and of dubious merit) hardware RTC that sits on the GPIO header. I'm using the bog-standard Pi Foundation plastic case.
It runs OpenWRT, which itself is very light-weight -- it's more-or-less just enough Linux to set up routing functions using a GUI, and it's meant to be able to fit in the tiny little bit of flash that consumer router hardware comes with.
IIRC, the status at the time when I put it together was that it could route packets and perform traffic shaping at ~1Gbps even with a USB NIC. It certainly did just fine when I had a 400Mbps pipe.