To improve the security of your k3s cluster you might want to set traefiks tls support to allow for tls v1.2 or greater.

This can be achived by deploying a TLSOption to the default namespace with the name default.

apiVersion: traefik.containo.us/v1alpha1
kind: TLSOption
metadata:
  name: default
  namespace: default
spec:
  minVersion: VersionTLS12  
  cipherSuites:
    - TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 # TLS 1.2
    - TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305  # TLS 1.2
    - TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384   # TLS 1.2
    - TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305    # TLS 1.2
    - TLS_AES_256_GCM_SHA384                  # TLS 1.3
    - TLS_CHACHA20_POLY1305_SHA256            # TLS 1.3
    - TLS_FALLBACK_SCSV                       # TLS FALLBACK

This will give you an A rating on ssllabs.com tecbeast.com SSLLabs Report by the time of writing this post.