To answer your question, no, I’ve not experienced an Ethernet disconnection.
My guess is that your Ethernet disconnection is a physical issue, either a dodgy cable or a wiggling Ethernet/USB adapter. I’ve experienced several connection dropouts with my MacBook Pro M1 because of a USB-C connection wiggling. Don’t get me started on the global incompetence of the USB consortium… Maybe they’ll finally get it right with USB-7G-Thundercloud-Delta or whatever they come up with in another couple decades. To quote a good friend I used to gig with, “In Heaven there are no cables.”
I would *not* rely on a WiFi connection for gigs, ever. Too many variables in an unknown environment. It’s unlikely you will even figure out that a microwave in the kitchen behind the bar is glitching your WiFi connection. Better to just stick with cables. (Same goes with Bluetooth connections.)
Even then, cables are notoriously faulty in a working musician’s environment. It’s something you’ll find worth carrying backups. If you have only one mic and only one mic cable, for example, you’re going to be stuck when that cable gets a loose connection. Sure, that cable has never had a problem while home, but these things happen when you are plugging/unplugging, coiling them up, or they’re being transported in a bag and tossed about. A mic cable only has 3 connections at each end, and an Ethernet cable is a mess of wires, so that’s just more chance for a problem.
I’m guessing you’re back to using your regular home WiFi network. Try going back to the direct Ethernet connection you used at the gig and see if you can replicate the problem. And if it happens, try a fresh Ethernet cable to see if it happens again.