Is QubesOS Template dangerous when connected to the internet?

I want to install VSCodium on QubesOS, but I want to launch it with a shortcut just like any other application. So I’m going to install from Template, but the question is here. Can I enable Network only when installing Template? I’ve heard that an operating system that has never been connected to the Internet is very safe. Which is safer, sys-firewall or sys-whonix?