How to access nextcloud data remotely installed in freenas 11.3 jail using wireguard

Hi everyone,
I have installed nextcloud in freenas 11.3 jail and is working locally. I can access my data in nextcloud. now I want to access it remotely. I have tried ngrok, zerotier but all gone in vain.
it has been month but I am failed trying. now surfing the web I got wireguard is default in freenas 11.3. please, someone help me with step by step instruction how to install and access Nextcloud remotely.
NOTE: MY ISP DOES NOT LET ME PORT FORWARD
Thank you in advance.