Windows XP Multiplayer Connectivity

I am having trouble playing multiplayer over the internet with two Windows XP SP3 computers, in that they are not connecting up to start the games. I can ping the host laptop with the host's firewall down. The host machine is connected to a Xfinity modem that is in bridge mode. The other laptop to my eero WiFi network which is connected to the Xfinity SB8 modem.

I can successfully connect and play multiplayer with the same laptops on my LAN Wi-Fi network, so there is no issue with the operating systems. They are Dell 830 laptops. 

I have two separate internet lines at my home. Two separate modems, IP, addresses, etc. The intention when the WAN (external internet) playing functionality is verified, to give the other laptop to my friend. I will be hosting the games on the modem in bridge mode.

These games will not play in W10 or W11. Port forwarding and DMZ does not work either for these Windows 98 games. I am fully aware that XP is not supported and is a security concern. I do not care if the laptop is hacked. I don't browse on the device anyway. That is what I have a separate network . . . but I need the direct IP address anyway . . . like it was in the old days.

Any help with configuration with connecting to the host PC would be appreciated.

Thank you!