I haven't followed the Heroes 7 topic for a while — turns out there's a massive 18.3 GB mod called Heroes 7.5, packed with tons of content and changes.

Added a wiki page about it https://heroesworld.ru/wiki/heroes-7/75/%D0%B3%D0%B5%D1%80%D0%BE%D0%B8-75-%D0%BE-%D0%BC%D0%BE%D0%B4%D0%B5/

The latest version can be downloaded here https://www.moddb.com/mods/heroes-of-might-and-magic-75/downloads/heroes-75-mod-145

It's probably worth checking out what the game will be like with this mod.