Gnome Desktop - bridging not working

HI there,

I want to set up a bridge on my tower (installed with the ISO / Gnome Desktop), which will be used with libvirtd for my local lab stuff.

I tried setting it up with:

networking = {
    interfaces = {
      enp34s0.useDHCP = true;
      br0.useDHCP = true;
    };
    bridges = { "br0" = { interfaces = [ "enp34s0" ]; }; };
  };

and

boot = {
    loader = {
         kernel = {
            sysctl = {
                # Enable traffic between interfaces
                "net.ipv4.conf.all.forwarding" = true;
                "net.ipv6.conf.all.forwarding" = true;
      };
    };
  };

My desktop has a DHCP reservation.

But when I add this, my wired interface goes offline, and I never get an address for the bridge. Could this be related to the networking components used in the gnome desktop config?

Thank you.

EDIT if I set it up in NMTUI The bridge will work. But I hate having this config missing from my nix files.