Check the Openwrt table of hardware[0] for a well supported device, and you're good to go. Seriously, there is no good vendor software in this space, but the consumer hardware can actually work fine with better firmware.

Generic Linux or BSD boxes are ok as routers, but they're not the best switches since they start taking up a lot of space if you need a bunch of NICs.

[0] https://openwrt.org/toh/start