I suspect that they'll announce that they've given PNG a provisional license with an eye to them entering the league some time around 2030 and that the 18th team will be the "Perth" Bears/Jets (almost certainly Bears) to enter in either 2026 or 2027. I also expect them to refrain from announcing the 20th team until a later date, but may or may not choose to announce that NZ is the preferred market.
What should happen is Perth should be given a license to enter in 26/27 independent of any other entity, then the NRL should sit and let them and the Dolphins settle in for at least a couple years before reviewing expansion. If things are going well expand to both NZ and Adelaide, keeping Brisbane in the pocket if either fall through.