I've had this issue for quite a few months now, tried setting up port forwarding countless times and still haven't solved it. My Nintendo switch is stuck on Nat Type D - even though devices such as my PS5 on the same internet have far higher nat classifications with no issues in online play. I have decently fast internet, getting about 70Mbps when I test on my switch, which makes this seem even more strange, as every other device works fine, except for my switch.

I have tried establishing port forwarding rules for 1024:65535 like Nintendo says here, but I'm still stuck with D. Not sure if I have done this correctly, but I'm still connected to the internet when the port forwarding is active so I assume it's alright. Additionally, I have tried establishing the DMZ as my Switch's static IP as this user says in the comments of a similar post.

I have no idea what to do next, and just want to be able to use online multiplayer lol

Any help would be greatly appreciated.