I don’t know if I’ve done this right (new member long time lurker) but it is to do with the latest firmware,with my Rt-BE86U i have noticed since updating the firmware to the latest release i now get Moderate Nat in games like Call of Duty on my PS5 where as it was Open Nat before the update and this is with Upnp re enabled,it does show in the port forward section that supposedly the ports are being opened but still remains Moderate I’ve always bought Asus routers because they gave me Open Nat but even using the latest Merlin firmware doesn’t help sadly 
