[meitham]

I am satisfied with pve and qm commands on proxmox, but I wish there was a nix answer to pfsense where my network and firewall are defined declaratively

[cromka]

This! pfSense/OPNSense seem to me like perfect candidates for declarative configuration. Even though, technically speaking, they are since everything is being save to a config file, which you can backup and restore. It's just less declarative then you'd like it to be. Sounds like they could easily employ Nix for handling that, though.

[leschak]

It is a scripting language but for Mikrotiks you can scp a .rsc file and

  ssh $username@$routeraddr '/import file=setup.rsc'

[finnlab]

Have you looked into VyOS?

[CrimsonCape]

Please evangelize me if you have experience and you consider this to be a better declarative containerized router...