HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

WoG/Era/TE/WoT?
If so, then yes, HD+ doesn't work and won't.
And there won't be any steps to increase the benefits for them.

I'll try to explain in detail.
I had The Shadow of Death, and I played with HD+ version 3.46. I determine the functionality of HD+ by the elimination of a bug (AI battles against each other are identical to battles against the player).

In 3.46, this bug didn't exist; after updating the mod, the bug appears.
I downloaded Heroes 3 Complete and installed the latest version of the HD+ mod - the bug is present.

I create a map where one AI attacks another AI. In 3.46, more than half of the army is killed; in the latest version of HD+, the losses are minimal.

Maybe it's a matter of settings, of various tweaks? I don't know.