Try to get your own broadband account password, and consult and confirm whether you can get the public network ipv4 address or ipv6 address. One of them must be used for remote streaming media, but now almost all broadband supports ipv6. If there is no public network ipv4 address, PS5 chooses to use ipv6 address flow, and the control terminal installed with PSRemotePlay must also be able to access ipv6 network for remote flow.
Ipv6 settings flow, the router sets ipv6 related settings (such as closing built-in ip management, deleting ipv6ULA prefix, setting ipv6 firewall, turning on DHCPv6, and turning off the prohibition of resolving IPv6DNS records). Different routers set different methods. If all goes well, IPv6 streaming can now be done through the external network.