Hello, I have recently set up a nextcloud server on my truenas scale machine. I am currently running the version: Dragonfish-24.04.2.5. Everything is running fine and functional, and I am able to upload while connected to internet. I now would like to advance to adding remote access so that I can access the nextcloud server an any network preferably using the nextcloud ios app and browser. I am not the best with linux but I know enough to have gotten this running. Thanks in advance!
You’ll need to look into setting up a reverse proxy.
Caddy and Traefik are two popular solutions.
If you want a solution that doesn’t require opening ports on your router:
“Additional” ports 
I use HA Proxy on OPNsense to access my services. No additional ports other than 80 and 443 are required to be open.
There are a few containers, such as stirling PDF, which I can’t get to work that way, so use the cloudflare tunnel for those.