That was in Windows Firewall with Advanced Security. What is a router firewall? Never had to deal with a router firewall when port forwarding other times.
Can you join regular minecraft at your external ip if you run it on on port 19132? Maybe your router doesn't have a firewall... but in addition to port-forwarding you should make sure that your ISP, router and computer don't have firewall rules that are blocking traffic.
Did you find a solution to this please? I run pocketmine server in a docker container, as I do many other apps that are port forwarded, however I cannot connect to this.