Most readers of HN will understand (or at least understand the goal of) the checklist for debugging network issues.
Skipping straight to Port Forwarding eliminates any issues on whether UPnP is actually working correctly. Growing up, some of my friends had routers struggled to handle UPnP correctly. If I knew they were the only one needing port forwarding, I'd simply turn that on for them instead of trying to figure out if UPnP was actually working correctly.
Most readers of HN will understand (or at least understand the goal of) the checklist for debugging network issues.
Skipping straight to Port Forwarding eliminates any issues on whether UPnP is actually working correctly. Growing up, some of my friends had routers struggled to handle UPnP correctly. If I knew they were the only one needing port forwarding, I'd simply turn that on for them instead of trying to figure out if UPnP was actually working correctly.