Since nobody has responded to the ACME / Let’s Encrypt part of the question yet, I’ll chime in: I also use Traefik as a reverse proxy (and an ACME client), one unified instance per machine. (There are some exceptions, like for Mailu that requires its own nginx reverse proxy.) But for Let’s Encrypt, I recently switched from the TLS challenge to the DNS challenge. That required switching my DNS server from CoreDNS to PowerDNS, but thus far it seems totally worth it. Now I can easily get TLS certs for servers on my private network at home without opening them up to the internet for HTTP/TLS challenges.