In a nut shell when your ISP is running CGNAT it's like a firewall in that no inbound traffic will reach your LAN unless a device on your LAN has started/opened a connection first. There are several work-arounds that I'd consider easy to complex.  A lot of this depends on the nature of how your remote access will be used.  If it's just you and family using mobile phones, tablets, computers on the go then the easier method is using a service such as TailScale that creates a private VPN.  Tai