So you have a modem from your ISP in bridge mode? Connected to an A7 acting as your router, which is connected to another A7 in AP mode? If not, then you might be dealing with a double NAT situation. You will want to confirm this is not the case if you have not done so already, and also eliminate CGNAT.
You could try setting a manual port forward instead of relying on UPNP.
And check here for more troubleshooting steps The Basics of Remote Access Troubleshooting
