Usually 169.254.169.254 holds node metadata on cloud environments like AWS or Hetzner. To deny access to it in a namespace use the following Network Policy:
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: deny-metadata
namespace: default
spec:
podSelector: {}
policyTypes:
- Egress
egress:
- to:
- ipBlock:
cidr: 0.0.0.0/0
except:
- 169.254.169.254/32