Port forwarding LAN IP or WAN IP, does it matter?

I have tried to put in both the WAN and LAN number shown in Bitcomet and im getting a green light from both. I dont use static IP or anything like that. Just want to know if one way is better than the other.

And a bonus question. I have heard that you shall turn off UpNP port mapping when port forwarding, but this doesn’t change anything from what I can see. Which option is the better one here?

Yes, it matters a lot. I’d suggest you start over, as you have some profound misunderstandings about what you’re doing.

If you aren’t setting up a static IP address between your computer and your router, then you don’t need a forwarded port to any address. Your computer’s address will change constantly, so any such thing would be hit-or-miss, depending on whether you just happened to be assigned the address where the port was forwarded, or not. There’d be no point in bothering with it.

UPnP is an attempt to automate port-forwarding. It’s great when it works. It’s impossible to either diagnose or fix if it doesn’t. Implementation has been very inconsistent, even from model to model. I prefer to do things manually, so that if anything changes I can adjust to it, whereas if UPnP fails, I’d have to do it manually anyway. UPnP error messages are strange, unhelpful. and you can’t do anything about it anyway since it’s all in firmware or in code you can’t touch.