Hi, since I have a Flint 2, I set one up as well for a friend, he has this setup where it's a Cable Modem / Router Combo Netgear Nighthawk X4S to an Orbi Mesh Network. This setup was working fine for him but no VPN or Adguard and such.
We removed the Orbi and replaced it with Flint 2, and Ethernet from WAN of Flint 2 goes into Lan of Netgear, it's set in DHCP on the Netgear as it was previously for Orbi but I can set it to static IP <-> Mac Addr of Flint 2 if needed to be.
So the Flint 2 works nicely (it's double nat-ed but he doesn't do port forwarding), it has NordVPN as VPN for certain IPs , Adguard is also working. But the Flint 2 goes offline every few hours and requires a reboot. Nothing in GlInet Crash log.
When this happens, the Netgear still has Internet, so it's something on the Flint 2 <-> Netgear connection. This never is an issue with his Orbi <-> Netgear, so wonder if something is causing this issue to happen.
I was curious how I should debug this issue... next time I am going to tell my friend to just remove the Ethernet cable from GliNet's Wan port and put it back in to see if it would renegotiate a new IP address.
Thanks for any suggestions/help.