Heroes of Might and Magic III on iOS and Android.

Okay, let’s assume that. But then, how do the following projects exist:
WOG
HotA
heroesland
Heroes 3 on Android?
You can find more information in the online heroes section, in the ports section, and so on. By the way, this topic would also look better in the ports section, in my humble opinion.

WOG and HotA are add-ons that use the original engine of the original game, so to speak, they are mods.

heroesland is a browser-based online game that uses the graphics of the third Heroes game, but has a slightly different gameplay mechanic. And I don’t think the developers of this project bought the rights, so Ubisoft may have grounds to file a claim here.

You can’t launch a large project, knowingly violating copyright.

I don’t know what this “mega” emulator for Android is, but I’m sure it’s something obscure