I did forget to mention that. The IP addresses of the devices on the LAN do not share the same first half of the address as the IP on the ISP router. I have the OPNsense LAN set to track WAN interface, but the DHCP server is stuck saying “No available address range for configured interface subnet size.”. I also noticed that my WAN for OPNsense has a global routable IP starting with 2402 as well as a LLA starting with fe80 but my LAN only has a LLA.

Which routes and firewall rules should I be checking?

I ultimately did go with Syncthing and uploading my files encrypted to Google Drive for backup. It’s been working great for months. I’ve also been using Zeroteir to make this work with my laptop too while on the go.

Thanks, I’ll look more into it.