For Steam you will have to forward the necessary ports.
https://help.bungie.net/hc/en-us/articles/360049496751-Advanced-Troubleshooting-UPnP-Port-Forwarding-and-NAT-Types
For Xbox and PlayStation you can put one console in the dmz or on the public ip address.
You will have to configure these settings in your router.
To get to that page open a cmd and type “ip config/all” look for default gateway and take note of this ip address. Next open a browser and type in that ip address in the url search bar.
You will now be at your router’s log in screen. I can’t help you any further as every router is different.
Microsoft identities an open nat as “Open” and Sony identifies it as “Type 1”.
Do not put a computer on the dmz as it’s a huge security risk. It’s safe to put a console on the dmz as they don’t face the same type of security risks a computer does.