Unity isn’t a game engine. It’s a malware-pushing advertising network which merged with a game engine to acquire a delivery channel and now wears its skin. This is fine for the bigger devs and publishers structured around platform relationships, but for everyone else? Gamemaker, Godot, Unreal, Defold… pick a flavor, they’re all on square one.
FYI the accusations that were flying when they merged with IronSource were misleading: IronSource malware came from “bad actors who abused the platform”
Not that it makes it any better, they will somehow be tracking installs anyway. Inaccurately, since they went from "The creator will need to pay for all future installs. The reason is that Unity doesn’t receive end-player information, just aggregate data" to "The spirit of this program is and has always been to charge for the first install and we have no desire to charge for the same person doing ongoing installs" in the span of 24 hours. I'm having a hard time trusting anything they say.
Even if they are not currently lying and have the magical ability to determine the exact number of installs. They have shown that they will arbitrarily change their pricing structure. There is no way they can be trusted. Anyone who can move their project to a new engine would be wise to do so.
Even if they aren’t lying and have the magical ability to determine the exact number of installs, some asshole is going to create a bot net which spams unique installs for developers they don’t like, skyrocketing the number of “installs” and therefore the cost to do business.