That screen is just ZimaOS waiting on DHCP. because your SMB shares keep working while the GUI drops, this smells like a lease/DNS wobble, not a dead link.
The clean fix: give the NAS a DHCP reservation on your Orbi, then mirror it in ZimaOS with a static IPv4, gateway, and manual DNS (1.1.1.1 / 9.9.9.9). on a lot of Realtek/2.5G mini-PCs, flipping off Energy-Efficient Ethernet helps too: find your interface (ip -o link …) and run ethtool --set-eee <iface> eee off. keep MTU at 1500 and disable any “green ethernet/EEE” toggle on the router. if it ever flakes, you can recover without a hard reboot by bouncing the link (ip link set <iface> down; sleep 2; ip link set <iface> up) and, if you’re on DHCP, dhclient -v <iface> usually brings the GUI right back. for quick forensics after a drop, check journalctl --since "10 min ago" | grep -i -E "dhcp|carrier|link|r816|realtek" and ethtool <iface>. and just to add: ZimaOS has been the best I’ve used—super simple to run and to tinker with—but that’s ultimately a personal call based on your setup.
sources: ZimaOS Reset Network Settings (https://www.zimaspace.com/docs/zimaos/resetnetworksettings), community walk-through on setting a static IP (https://community.zimaspace.com/t/tutorial-how-to-set-a-static-ip-address/3225), NETGEAR’s guide to DHCP reservations (https://kb.netgear.com/25722/How-do-I-reserve-an-IP-address-on-my-NETGEAR-router), the ethtool manual for --set-eee (https://www.man7.org/linux/man-pages/man8/ethtool.8.html), the journalctl manual (https://www.man7.org/linux/man-pages/man1/journalctl.1.html), and a practical reference on mDNS/.local name resolution with Avahi (https://github.com/balena-io-examples/balena-avahi).