@ncts @aya gentoo also do that, but they provide some workaround:
1. for golang packages, they now force packagers to provide "vendor" tarballs
2. they allow -9999 (live) packages to access the internet when building.

btw I actually get #1 work with Guix too, so maybe I'm wrong, you can hack Guix any way you want after all.

Failed to learn/play with Guix again... It's impossible to package a golang software (such as v2ray) as it requires all dependencies be packaged by Guix... even if your go.sum contains thousands of lines lol 🙃