Hi,
Just as another user who was facing the same issue with EE's NAT Type 3 during gaming I found a solution that might work for you, although NAT type was still 3 no lag or connection issues have occurred during gameplay yet.
Things I did first was to set a static IP on the PS5 Console (using a wired ethernet cable preferably to get the IP address, Subnet Mask and Default Gateway of the connected network) and going into network settings and advanced settings of the connected network and putting these values into the manual section of IP Address Settings.
Second was to access the routers page and going into Port Forwarding section and putting the PS5 values for better network connectivity based on the ones provided by PS5 and the game you want to play.
Although when I tested it with just this setting it didn't make too much of a change so the last step was to go into security section of the router or wherever you can find IP Binding and then bind the specific IP and Mac Address of the PS5 to it and then activate the DMZ option and enter the PS5's IP address, this seemed to fix the issues with the connection dropping and making games unplayable for me atleast.
I hope this helps you or anyone out in a similar situation as I was struggling with getting games to play properly but seemed to be fixed with these settings.
