Based on your question above, you play online games with your Xbox One and now you are not able to do so after the switch, am I correct?
Though I cannot explain how the PS5, based on my understanding of Xbox One it needs port forwarding to play online. Home Wireless use CG-NAT and port forwarding would not work with this set up.
What is CG-NAT and how does it affect Home Wireless Broadband Services?
Techy types should be aware that Home Wireless Broadband uses CG-NAT. Carrier-grade NAT (Network Address Translation) is a type of network that assigns services with a private IP address, instead of a dynamic public IP address. Our network will then translate that private address into a public address. This means that the following items (which depend on internal NAT) will not work on Home Wireless Broadband: