So there are a ton of new Intel I225 devices on the market which make perfect Gbit+ routers. I have been using OpenWRT for years as my go-to router for x86 and got one of the Topton Celeron N5105 embedded CPUs. Unfortunately none of the X86 builds have kmod-igc in the builds by default, and my usb nics arent supported out of the box either.
I was able to get it going by manually installing the kmod from a USB stick, but not everyone would want to have to go to that extent.
You can add any modules you need, by using the image builder.
To frollic's point, you can create a custom image for your hardware with the image builder, including any customisations you need for things like VLANs etc. This means you can rebuild your device at any point, and not have to deal with manual setup (to a large extent). Also useful if you need to build more than one machine.
https://www.cricalix.net/2022/06/13/building-a-custom-openwrt-image/ are my notes on doing it, put together from various wiki pages for the project.