Does the device show up if you open Gparted? Maybe it needs to be formatted. Though I guess it’d still show up with ‘lsusb’ even if it needed formatting.

I wanna say fwupd/lvfs manages firmware updates on Arch (and lots of other distros) these days.

You may be able to roll back the latest firmware update with fwupdmgr. What’s the output of fwupdmgr get-devices in your terminal? Also, what is the make/model of the ethernet port that is now on the fritz? You can search for it on the website here: https://fwupd.org/ in the “search for firmware” bar at the top, then you may be able to install the old version with fwupdmgr.

I’m not familiar with EndeavourOS, but I’ll ask a few questions to get the troubleshooting process started:

With the ethernet cable plugged in, can you access your local router config page (if you have one)? e.g.: 192.168.1.1. If not, what happens when you ping the router’s address in the terminal?

If you’re able to successfully ping/access your router, can you ping a well-known IP address such as 8.8.8.8 (google DNS) or 1.1.1.1 (cloudflare DNS)?