I have a beaten-up old desktop machine driving my router and an all-in-one PC (basically a screen in a thick case that has a motherboard and disk, etc, in it) driving my mill and both use wired Ethernet to the motion controller and Wi-Fi to house network - which can be a bit flaky as it uses Ethernet-over-mains adaptors. In practice, though, the house network is only used to download gcode and it has nothing to do with the actual cutting process so reliability and speed aren't so critical. I would never want to use files on a network file server during the cutting process, for example - I always use a local copy.

I don't know what the buffer size that UCCNC uses is, but I would be very surprised if it cannot cope with any very slight delays in the network processing. The data rate is well within the USB speed which is probably the limiting factor. I'm with Doddy - doubt if you'll have any problems.