UPnP means "Universal Plug and Play," and it's a router configuration. The UPnP Not Successful in Xbox One or Xbox Series error is tweaking your home network
Double NAT can be pretty annoying. Here's how you can fix it and why it happens. Double NAT (Network Address Translation) can be pretty annoying since it can lead to some audio issues.
Windows has an effective firewall built in, your home network adds another layer, and your security suite comes with a firewall. Is the third-party personal firewall utility dead?