Xcode has an iOS simulator. You can have a macOS VM run xcode.

I have an extensive config inclduing vlans, plugins, policies, suricata, VPN, routes, gateways, HAProxy, etc.

When you have an extensive config, you should always test the upgrade on a “lab” machine before applying them to your “production” environment. You don’t just apply the update blindly and hope nothing breaks.

I use RapidCRC.

Use PAR files like the others suggested.

Or use WinRAR’s recovery volumes.