I am hosting an Elixir application using Gigalixir (a PaaS like Heroku). For custom domains, it asks you to add a CNAME record to point to their custom DNS domain, e.g.
www.example.com.gigalixirdns.com. -- this works great for the
www version of the domains.
However, because of the RFC rules for DNS, you cannot define a CNAME rule for the non-www/apex/root domain. Some registrars allow an ALIAS record to deal with this (like namecheap). But Route 53 doesn't work the same way. It has "aliases", but I cannot make them point to an external domain for resolution.
My domain Hosted Zone (i.e. Zone File) only has an NS, SOA, and a CNAME for the www version of the domain (which works). It does not need to support email or anything else. I cannot make an alias for the apex domain point to the existing CNAME either.
I know similar questions have been asked, but so far I cannot come up with any combination that makes the root level domain work for HTTPS requests. Can someone shed light on this?