I tried caddy-l4 to pass through client authentication and also client authentication offloading but with no luck

There is no restriction to using a different proxy besides Caddy, it's just the default. It may be a better idea to leave Caddy implementation as-is and have a stable alternative which will proxy MQ using Nginx, HAProxy, or Traefik

Do you have working solution for this? I’ll try Nginx plus that looks promising.