Connecting it from the client, you first will need to satisfy negotiation of the TLS handshake and certificate hostname verification.
Can you assume that your server IP won’t change?
Assuming it won’t change, then add the DNS and its IP to your clients /etc/hosts file, and then continue to use the DNS in the mender client config. However, this means you are no longer using external DNS at all, as you are using the local device’s resolver, this may not be what you want. Generally, I only use this for development work rather than production work, but your needs may vary.