NatPMP is a different protocol than UPNP. It works similar but is not the same. I can confirm that Mikrotik does not support NatPMP but UPNP does work. The program I am using Homebridge uses NatPMP which is a protocol used most by Apple devices. It tries to open the ports but doesn't work on Mikrotik. If i boot up my PFSense firewall as an example which supports NatPMP the ports get opened.
Here is an article on Wikipedia explaining NatPMP