Access HTTPS Server through OpenVPN to bypass CGNAT

Hello,
I have recently discovered that my ISP is using carrier grade NAT, making the use of the DuckDNS docker spotty at best. I have a Nextcloud appliance that I would like to access through the web (uses separate internal IP), and I would like to know if is possible to access this server by connecting to OpenVPN, then port forwarding through OpenVPN to port 443 through my router, and having the router point to my internal server IP (OpenVPN Port 443--> Router port 443--> Internal server IP address)? Also, would DuckDNS be able to automatically update the VPN IP address so that the appliance can be accessed if there is a change to the VPN WAN IP address? Forgive me if I have omitted any details as I am relatively new to Linux and Networking, and basically just follow tutorials for any CLI based interactions. Currently the server is just accessed through port 443 using DuckDNS.