Custom routing rules for specific services

k3s, k3OS, and k3d
1

Good Day!
In our K3S cluster hosten on Hetzner we have a service that produces outbound traffic to reach an external Postgres DB. The database server expects that the IP will stay the same for whitelisting traffic.
To esure that the whitelisting rules should never change, we use Hetzner Flaoting IPs. Effectively attaching a static, reserved IP to any VM.

The network interface eth0 has two public IPs

~ # ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    inet <default_vm_IP>/32 brd <default_vm_IP> scope global dynamic eth0
       valid_lft 65611sec preferred_lft 65611sec
    inet <floating_IP>/32 brd <floating_IP> scope global eth0

For now the service could have such a definition. So every node in the cluster would be whitelisted for the external Postgres DB

apiVersion: v1
kind: Service
metadata:
  name: pg-client
  namespace: pg-test
spec:
  selector:
    app: pg-client
  type: NodePort
  ports:
  - name: pg-client
    protocol: TCP
    port: 5432
    targetPort: 5432  
    nodePort: 32345

The problem is that outgoing traffic always uses default_vm_IP, but it is desired that floating_IP is used.

Reconfiguring K3S has not resulted in the desired effect

curl -sfL https://get.k3s.io | sh -s - agent \
    --token=${token} \
    --node-ip=$floating_ip \
    --server="https://${master_node_ip}:6443" \
    --kubelet-arg="cloud-provider=external" \
    --node-external-ip="$floating_ip" \
    --flannel-iface=$private_network_iface

My next best guess would be to create additional IP tables rules that will force the routing of the pg-client Kubernetes service, to route through that specific floating_ip. But I have no idea how to achieve this.

Any advice on how achieve such a behaviour?
Best Regards