You're right, but it's not that they want less illegal immigration.
They want everyone to migrate to the same centralized location, where they can be easily surveilled and controlled.
If your goal is control, it’s far easier to monitor people once they’ve come to you, rather than trying to track them across dispersed locations.
By offering incentives for illegal migration, people will come. And while that influx happens, they quietly build out the surveillance infrastructure, expanding it as the population grows.
Trying to build and maintain a global surveillance grid is inefficient. It's much more effective to concentrate the cameras, 5G towers, surveillance vehicles, and infrastructure in one place.