DNSSEC is completely different form DNS over TLS. To enable it, you need to go to services > UnboundDNS > DNS over TLS. You can use cloud flare DNS (1.1.1.1) with port 853 to enable it. I would recommend forcing all traffic on port 53 to go to unbound through the firewall. After you set it up, verify by using the cloudflare site for testing DNS over TLS. It can only test cloudflare DNS over TLS so if you use another DNS you need to find a way to verify that. Good Luck!
"