I want to configure a network IP, which requires that no matter what IP address, I can go out from this network port to surf the Internet.

The first problem is that data cannot be routed to the main gateway. Reconnect the WAN port of the guest router to the hotel router and get the IP address through DHCP. In addition, the WAN port in the customer router should be set to DHCP mode, and then the customer computer should be plugged into the LAN port to access the Internet. You can also use the guest router as a switch, just turn off the routing function of the router and stop the DHCP service.

The second question, which you asked is a bit confusing, is also very simple to do. Directly set the guest's computer as DHCP to obtain IP. If he must have a router, just like the first question above, set the WAN port to DHCP, and set the computer to the same IP segment or DHCP to obtain IP.