Hi,
I would recommend you spend a bit of time reading the forum.
Have a look at:
https://www.ixsystems.com/community...llation-of-nextcloud-16-in-iocage-jail.62485/
There is a lot of info to swallow for a first time user.
At least, for started you just need to be able to setup Netcloud without authentication to get you started with somewhat minimal issues, but then again, any step you take is full of caveats.
If you want to expose Nextcloud to the internet, then you need a domain name, best to use a wildcard domain.
Then you need a firewall such as pfsense and use a proxy server such as Haproxy to handle domain name routing to your nextcloud IP.