it would help if you showed us your config.php to see if there’s something missing
a reverse proxy is generally recommended if you want to host multiple services, see 101: Network, domain and DNS and Reverse proxy configuration personally i use NMP see NGINX proxy manager · nextcloud-snap/nextcloud-snap Wiki · GitHub and be sure to read How to manage Hosts and FQDN for Nextcloud snap
generally though, if you’re not prepared to enable public access with lets encrypt certificates, you’re on your own. self signed certificates are possible but your instance almost unusable.